SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'db9823d7e4cb88506bb254182ca258ffa39ce970999c277c2d52917d76a95335' 
  AND token = 'arrdUnYxbk3FoAqZW2rcdJSjyKVkcNzaymDo1ufnKQs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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