SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c41f2246f348cd98f765a722366ab0b988c2221bf2496f41f9ef779f306d260f' 
  AND token = 'h5xL/TFzElQ4igelwVuWM8iPNmbg6mm36biJGmPPcKU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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