SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1cf0084c9bc9300d80b7a9a14aa320f3664a1be16fcce464dabd88dd2dc686e7' 
  AND token = '9ZnZjvNO3aFULI/LKIvbTwBko+NJgHFsrmExzmVlPew=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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