diff --git a/app/Services/UserService.php b/app/Services/UserService.php
index 45c4802..f02091b 100644
--- a/app/Services/UserService.php
+++ b/app/Services/UserService.php
@@ -9,7 +9,7 @@
 {
     private static function lastSeenKey(int $userId): string
     {
-        return sprintf('last_seen_%d', $userId);
+        return sprintf('last_seen:%d', $userId);
     }
 
     public static function setLastSeen(int $userId, ?Carbon $seenAt = null): void