SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '041c891e0140787c2d9a7af2a7af52b4d3afcdf8958ab15e6f1997de4bd62490' 
  AND token = 'pLXKjmyBnNIEINJsIOLv4Hh6IMQKN+ZYCjjBaQgzPcA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}