diff --git a/src/Symfony/Component/Lock/Store/MongoDbStore.php b/src/Symfony/Component/Lock/Store/MongoDbStore.php
index e720f8d1c1299..d6cb8f96e6288 100644
--- a/src/Symfony/Component/Lock/Store/MongoDbStore.php
+++ b/src/Symfony/Component/Lock/Store/MongoDbStore.php
@@ -169,8 +169,8 @@ public function createTtlIndex(int $expireAfterSeconds = 0): string
      */
     public function save(Key $key)
     {
-        $token = $this->getUniqueToken($key);
         $now = microtime(true);
+        $token = $this->getUniqueToken($key);
 
         $filter = array(
             '_id' => (string) $key,
@@ -244,6 +244,7 @@ public function waitAndSave(Key $key)
     public function putOffExpiration(Key $key, $ttl)
     {
         $now = microtime(true);
+        $token = $this->getUniqueToken($key);
 
         $filter = array(
             '_id' => (string) $key,