SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1fee67a4de60ef97a2c1bccb8a05c4f765fd0131cf94645c3f6d60332f643557' 
  AND token = 'pVm0YoXWHcI63KkDU6SxKCAXBgSi2WY+zSwRwW56UWA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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