diff --git a/moto/dynamodb2/models.py b/moto/dynamodb2/models.py
index fb34e19cc..bfbb654b4 100644
--- a/moto/dynamodb2/models.py
+++ b/moto/dynamodb2/models.py
@@ -985,8 +985,7 @@ class DynamoDBBackend(BaseBackend):
         else:
             filter_expression = Op(None, None)  # Will always eval to true
 
-        projection_expression = ','.join([expr_names[attr] if attr in expr_names else attr
-                                          for attr in projection_expression.replace(' ', '').split(',')])
+        projection_expression = ','.join([expr_names.get(attr, attr) for attr in projection_expression.replace(' ', '').split(',')])
 
         return table.scan(scan_filters, limit, exclusive_start_key, filter_expression, index_name, projection_expression)