diff --git a/app/code/Magento/Security/Model/AdminSessionInfo.php b/app/code/Magento/Security/Model/AdminSessionInfo.php
index c14d399e98cac..60053357f0ae7 100644
--- a/app/code/Magento/Security/Model/AdminSessionInfo.php
+++ b/app/code/Magento/Security/Model/AdminSessionInfo.php
@@ -132,7 +132,7 @@ public function isSessionExpired()
         $lifetime = $this->securityConfig->getAdminSessionLifetime();
         $currentTime = $this->dateTime->gmtTimestamp();
         $lastUpdatedTime = $this->getUpdatedAt();
-        if (!is_numeric($lastUpdatedTime)) {
+        if (is_string($lastUpdatedTime)) {
             $lastUpdatedTime = strtotime($lastUpdatedTime);
         }