diff --git a/bigchaindb/backend/localmongodb/query.py b/bigchaindb/backend/localmongodb/query.py
index 5ad6a0a0..effbdacb 100644
--- a/bigchaindb/backend/localmongodb/query.py
+++ b/bigchaindb/backend/localmongodb/query.py
@@ -91,11 +91,10 @@ def get_assets(conn, asset_ids):
 
 @register_query(LocalMongoDBConnection)
 def get_spent(conn, transaction_id, output):
-    query_array = [{'transaction_id': transaction_id,
-                   'output_index': output},
-                   {'output_index': output,
-                    'transaction_id': transaction_id}]
-    query = {'inputs.fulfills': {'$in': query_array}}
+    query = {'inputs':
+             {'$elemMatch':
+              {'$and': [{'fulfills.transaction_id': transaction_id},
+                        {'fulfills.output_index': output}]}}}
 
     return conn.run(
         conn.collection('transactions')
@@ -184,15 +183,18 @@ def get_owned_ids(conn, owner):
 
 @register_query(LocalMongoDBConnection)
 def get_spending_transactions(conn, inputs):
+    transaction_ids = [i['transaction_id'] for i in inputs]
+    output_indexes = [i['output_index'] for i in inputs]
+    query = {'inputs':
+             {'$elemMatch':
+              {'$and':
+               [
+                   {'fulfills.transaction_id': {'$in': transaction_ids}},
+                   {'fulfills.output_index': {'$in': output_indexes}}
+               ]}}}
+
     cursor = conn.run(
-        conn.collection('transactions').aggregate([
-            {'$match': {
-                'inputs.fulfills': {
-                    '$in': inputs,
-                },
-            }},
-            {'$project': {'_id': False}}
-        ]))
+        conn.collection('transactions').find(query, {'_id': False}))
     return cursor
 
 
diff --git a/bigchaindb/common/transaction.py b/bigchaindb/common/transaction.py
index f4456396..a1dfc626 100644
--- a/bigchaindb/common/transaction.py
+++ b/bigchaindb/common/transaction.py
@@ -274,12 +274,6 @@ class TransactionLink(object):
                 'output_index': self.output,
             }
 
-    def to_query(self):
-        return [{'transaction_id': self.txid,
-                 'output_index': self.output},
-                {'output_index': self.output,
-                 'transaction_id': self.txid}]
-
     def to_uri(self, path=''):
         if self.txid is None and self.output is None:
             return None
diff --git a/bigchaindb/fastquery.py b/bigchaindb/fastquery.py
index d17fb12d..0cf873cf 100644
--- a/bigchaindb/fastquery.py
+++ b/bigchaindb/fastquery.py
@@ -5,7 +5,6 @@
 from bigchaindb.utils import condition_details_has_owner
 from bigchaindb.backend import query
 from bigchaindb.common.transaction import TransactionLink
-from itertools import chain
 
 
 class FastQuery():
@@ -29,7 +28,7 @@ class FastQuery():
         Args:
             outputs: list of TransactionLink
         """
-        links = list(chain.from_iterable([o.to_query() for o in outputs]))
+        links = [o.to_dict() for o in outputs]
         txs = list(query.get_spending_transactions(self.connection, links))
         spends = {TransactionLink.from_dict(input_['fulfills'])
                   for tx in txs
@@ -42,7 +41,7 @@ class FastQuery():
         Args:
             outputs: list of TransactionLink
         """
-        links = list(chain.from_iterable([o.to_query() for o in outputs]))
+        links = [o.to_dict() for o in outputs]
         txs = list(query.get_spending_transactions(self.connection, links))
         spends = {TransactionLink.from_dict(input_['fulfills'])
                   for tx in txs
diff --git a/tests/test_core.py b/tests/test_core.py
index 85fc7ec3..d7bc4bb5 100644
--- a/tests/test_core.py
+++ b/tests/test_core.py
@@ -71,7 +71,7 @@ def test_get_spent_issue_1271(b, alice, bob, carol):
         [carol.public_key],
         [([carol.public_key], 8)],
     ).sign([carol.private_key])
-    assert b.validate_transaction(tx_1)
+    assert tx_1.validate(b)
     b.store_bulk_transactions([tx_1])
 
     tx_2 = Transaction.transfer(
@@ -81,7 +81,7 @@ def test_get_spent_issue_1271(b, alice, bob, carol):
          ([carol.public_key], 4)],
         asset_id=tx_1.id,
     ).sign([carol.private_key])
-    assert b.validate_transaction(tx_2)
+    assert tx_2.validate(b)
     b.store_bulk_transactions([tx_2])
 
     tx_3 = Transaction.transfer(
@@ -90,7 +90,7 @@ def test_get_spent_issue_1271(b, alice, bob, carol):
          ([carol.public_key], 3)],
         asset_id=tx_1.id,
     ).sign([carol.private_key])
-    assert b.validate_transaction(tx_3)
+    assert tx_3.validate(b)
     b.store_bulk_transactions([tx_3])
 
     tx_4 = Transaction.transfer(
@@ -98,7 +98,7 @@ def test_get_spent_issue_1271(b, alice, bob, carol):
         [([bob.public_key], 3)],
         asset_id=tx_1.id,
     ).sign([alice.private_key])
-    assert b.validate_transaction(tx_4)
+    assert tx_4.validate(b)
     b.store_bulk_transactions([tx_4])
 
     tx_5 = Transaction.transfer(
@@ -106,7 +106,8 @@ def test_get_spent_issue_1271(b, alice, bob, carol):
         [([alice.public_key], 2)],
         asset_id=tx_1.id,
     ).sign([bob.private_key])
-    assert b.validate_transaction(tx_5)
+    assert tx_5.validate(b)
+
     b.store_bulk_transactions([tx_5])
 
     assert b.get_spent(tx_2.id, 0) == tx_5