Mung beans take 10+ days to sprout
Most seeds need warmth to sprout.  When I'm starting beans at home (to grow, not to eat directly), I either use a 'seed mat' (electrical heating pad), or a lamp set realy close to the soil.  In both cases, I keep the seeds in a clear-topped container, so that they don't dry out -- the moisture gets trapped in and makes a mini-greenhouse.

You can likely rig up a similar system using household items:


Place a couple of damp paper towels in the bottom of a baking dish (9"x13" if you have it)
Spread the seeds on top of the towels
Cover the baking dish tightly with plastic wrap (aka cling film)
Set it in a sunny window
Wait


After a day in the sun, you should see moisture forming on the inside of the plastic wrap.  Tap it a few times to get the water to drop back onto the sheet (and let the sun through better).

If you have a heating pad, you can try that, too, but you don't want to leave it on all day, as you need a 'day' and 'night' time for most plants to sprout.  (and I don't know how hot they get ... they might get too warm.)