SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '66ce3f0dfbd0dc8179db24eb7d23496e64aa87fc7090f25ebf4f85e73bf9889c' 
  AND token = '3diJaJmHFrKKfsqA7Hzc4MWGjZnMtjXDSXCBD8/rpgo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00064

JSON explain

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