Villains at 5nl LOVE to play Aces with anything and like StarGrinder said 5nl villains can't get away from TP even with a shit kicker, which means that he could have Ax, 33, 24 (HAHA). I'd still shove, even though he might have AA. I doubt he does though... a lot of people when they flop a set or a straight will try to slow play and check.
His bet sizing on the flop seems more like he's got A3 and got overexcited about his two pair.