diff --git a/django_rq/tests/utils.py b/django_rq/tests/utils.py
index afe4df2a..8b467f7a 100644
--- a/django_rq/tests/utils.py
+++ b/django_rq/tests/utils.py
@@ -5,15 +5,18 @@ def get_queue_index(name='default'):
     """
     Returns the position of Queue for the named queue in QUEUES_LIST
     """
-    queue_index = None
     connection = get_connection(name)
     connection_kwargs = connection.connection_pool.connection_kwargs
+
     for i in range(0, 100):
         try:
             q = get_queue_by_index(i)
         except AttributeError:
             continue
-        if q.name == name and q.connection.connection_pool.connection_kwargs == connection_kwargs:
-            queue_index = i
-            break
-    return queue_index
+        if q.name == name:
+            # assert that the connection is correct
+            assert q.connection.connection_pool.connection_kwargs == connection_kwargs
+
+            return i
+
+    return None
diff --git a/django_rq/utils.py b/django_rq/utils.py
index d5b0a536..36b92368 100644
--- a/django_rq/utils.py
+++ b/django_rq/utils.py
@@ -67,9 +67,10 @@ def get_statistics(run_maintenance_tasks=False):
         else:
             oldest_job_timestamp = "-"
 
-        # parse_class and connection_pool are not needed and not JSON serializable
-        connection_kwargs.pop('parser_class', None)
+        # remove unneeded properties which are not serializable in JSON
         connection_kwargs.pop('connection_pool', None)
+        connection_kwargs.pop('parser_class', None)
+        connection_kwargs.pop('retry', None)
 
         queue_data = {
             'name': queue.name,