SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '398ceaa628d2299febf5576260378a43e03fce07ee197cab93858b1326e2ce89' 
  AND token = 'xVhWfMrfOP+3HmcIJvq4mp9SKUUs/bI1ptpn1ir8X4E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00060

JSON explain

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