SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6aaa3f9e047c1844924440bbb3d65739ecc40f78cad9b120dc967ce5d7b30660' 
  AND token = '0uMtUMkLwoDaZGGJ93fJINy0rX/d1zMkdfrew2LK/Tk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

Explain
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE Impossible WHERE noticed after reading const tables