diff --git a/cassandra/cluster.py b/cassandra/cluster.py
index c76ccb99..fc6b22af 100644
--- a/cassandra/cluster.py
+++ b/cassandra/cluster.py
@@ -3355,7 +3355,7 @@ class ResponseFuture(object):
         errors = self._errors
         if not errors:
             if self.is_schema_agreed:
-                key = self._current_host.address if self.current_host else 'no host queried before timeout'
+                key = self._current_host.address if self._current_host else 'no host queried before timeout'
                 errors = {key: "Client request timeout. See Session.execute[_async](timeout)"}
             else:
                 connection = self.session.cluster.control_connection._connection