diff --git a/jwt/api_jwt.py b/jwt/api_jwt.py
index 4bb1ee1f..77857d27 100644
--- a/jwt/api_jwt.py
+++ b/jwt/api_jwt.py
@@ -187,7 +187,7 @@ def _validate_claims(self, payload, options, audience=None, issuer=None, leeway=
 
         self._validate_required_claims(payload, options)
 
-        now = timegm(datetime.now(tz=timezone.utc).utctimetuple())
+        now = datetime.now(tz=timezone.utc).timestamp()
 
         if "iat" in payload and options["verify_iat"]:
             self._validate_iat(payload, now, leeway)