I know this is not using moment, however this is in the format you want
Check this out.
http://jsfiddle.net/robbmj/czu6scth/2/
window.onload = function() {
var display = document.querySelector('#time'),
timer = new CountDownTimer(5);
timer.onTick(format).onTick(restart).start();
function restart() {
if (this.expired()) {
setTimeout(function() { timer.start(); }, 1000);
}
}
function format(minutes, seconds) {
minutes = minutes < 10 ? "0" + minutes : minutes;
seconds = seconds < 10 ? "0" + seconds : seconds;
display.textContent = minutes + ':' + seconds;
}
};
This will display in 00:00 format.