Billy Paynter opened the scoring for Swindon on 18 minutes with a headed goal.
Wilbraham equalised for Milton Keynes on 27 minutes with a goal from close range.
Swindon had more chances to score before the break, but couldn't get the ball into the back of the net. Simon Cox hit the bar from close range with an open goal in front of him.
Swindon then went on to miss chance after chance in the second half with Paynter hitting the post this time, and Cox missing the rebound.
Milton Keynes were reduced to ten men with 5 minutes to go when Lewington was shown his second yellow card of the game.
Overall a good game, but Swindon should have won and could have got 4 or 5 goals on another day.