diff --git a/extensions/lock/migrations/2018_09_15_043621_add_discussions_indices.php b/extensions/lock/migrations/2018_09_15_043621_add_discussions_indices.php
index 01d92f99e..c588618fc 100644
--- a/extensions/lock/migrations/2018_09_15_043621_add_discussions_indices.php
+++ b/extensions/lock/migrations/2018_09_15_043621_add_discussions_indices.php
@@ -9,19 +9,24 @@
  * file that was distributed with this source code.
  */
 
+use Flarum\Database\Migration;
 use Illuminate\Database\Schema\Blueprint;
 use Illuminate\Database\Schema\Builder;
 
 return [
     'up' => function (Builder $schema) {
-        $schema->table('discussions', function (Blueprint $table) {
+        $schema->table('discussions', function (Blueprint $table) use ($schema) {
             $table->index('is_locked');
+
+            Migration::fixIndexNames($schema, $table);
         });
     },
 
     'down' => function (Builder $schema) {
-        $schema->table('discussions', function (Blueprint $table) {
+        $schema->table('discussions', function (Blueprint $table) use ($schema) {
             $table->dropIndex(['is_locked']);
+
+            Migration::fixIndexNames($schema, $table);
         });
     }
 ];