SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9340f3882aadb82cf26a9d9a6ec273f2b5b6ae9b18ca881f4dfcff0c24dd5966' 
  AND token = '07Edb8WDPKFTjpgQ9oHfu566pWmj+kuJXFK1+dnJlY4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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