diff --git a/synapse/crypto/keyring.py b/synapse/crypto/keyring.py
index a692cdbe55..e251ab6af3 100644
--- a/synapse/crypto/keyring.py
+++ b/synapse/crypto/keyring.py
@@ -162,7 +162,9 @@ class Keyring(object):
         def remove_deferreds(res, server_name, group_id):
             server_to_gids[server_name].discard(group_id)
             if not server_to_gids[server_name]:
-                server_to_deferred.pop(server_name).callback(None)
+                d = server_to_deferred.pop(server_name, None)
+                if d:
+                    d.callback(None)
             return res
 
         for g_id, deferred in deferreds.items():
@@ -200,8 +202,15 @@ class Keyring(object):
             else:
                 break
 
-        for server_name, deferred in server_to_deferred:
-            self.key_downloads[server_name] = ObservableDeferred(deferred)
+        for server_name, deferred in server_to_deferred.items():
+            d = ObservableDeferred(deferred)
+            self.key_downloads[server_name] = d
+
+            def rm(r, server_name):
+                self.key_downloads.pop(server_name, None)
+                return r
+
+            d.addBoth(rm, server_name)
 
     def get_server_verify_keys(self, group_id_to_group, group_id_to_deferred):
         """Takes a dict of KeyGroups and tries to find at least one key for
@@ -220,9 +229,8 @@ class Keyring(object):
             merged_results = {}
 
             missing_keys = {
-                group.server_name: key_id
+                group.server_name: set(group.key_ids)
                 for group in group_id_to_group.values()
-                for key_id in group.key_ids
             }
 
             for fn in key_fetch_fns:
@@ -279,16 +287,15 @@ class Keyring(object):
     def get_keys_from_store(self, server_name_and_key_ids):
         res = yield defer.gatherResults(
             [
-                self.store.get_server_verify_keys(server_name, key_ids)
+                self.store.get_server_verify_keys(
+                    server_name, key_ids
+                ).addCallback(lambda ks, server: (server, ks), server_name)
                 for server_name, key_ids in server_name_and_key_ids
             ],
             consumeErrors=True,
         ).addErrback(unwrapFirstError)
 
-        defer.returnValue(dict(zip(
-            [server_name for server_name, _ in server_name_and_key_ids],
-            res
-        )))
+        defer.returnValue(dict(res))
 
     @defer.inlineCallbacks
     def get_keys_from_perspectives(self, server_name_and_key_ids):