Примерно так:
setTimeout(() => {
const url = 'https://api.vk.com/method/users.get';
const data = 'Y=YparameterValue&Z=ZparameterValue';
const xhr = new XMLHttpRequest();
xhr.open('POST', url, true);
xhr.setRequestHeader('Content-type', 'application/x-www-form-urlencoded');
xhr.send(data);
}, 5000);