SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '635e6c35a09a590e9f0239166afcdf912e70b032dcfe3cd87a8071df2ef747ae' 
  AND token = 'jf9Lkz2N11tGWKOdDzRTkoyDlCAsxlwmpbneh1iJU+4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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