SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '239a53c83da4cb4136e220174e9148dce38702549d77431468ddba06c173af64' 
  AND token = 'f4PFMP6uDNGxGySrF14HWRBeA8pdwJVOy4kZgzZMPqI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}