I think this is a pretty easy call. You are getting close to 3-1 on your call, and you have what I would consider a guaranteed 6-outs if you are behind. You have about a 25% chance of winning in that case, so your call is correct (my math might be a bit off, it's off the top of my head). In addition, I could definitely see him having either TT or
[Kh] or
[Qh]. Maybe even
[Th], as farfetched as that may sound. Overall, you have several outs (in addition to the backdoor that you hit) and you are getting great odds to hit against a suspect player, I think you have to make the call everytime.
Oh and one more thing - I think I would prefer betting out here for two reasons. One is that while it is great that he will probably bet an unimproved AK, you also have to contend with button, and if he calls a weak bet from MP you have to put in a sizable raise to try to get both of them out. I don't think this is a hand where you want to play for your stack. At least one of them could easily have picked up a flush draw, and if you bet pot then the chances of them folding are much greater, rather than if they already put money in the pot and it is big enough that they are getting correct odds. Second, if MP happens to have woken up with a real hand, then you are gonna be in trouble after checkraising. The problem is that every pocket pair 7s and up beats you, with the exception of TT, which has some heavy draws. There is a good chance he raised with a pocket pair, so unless he has AK or AQ you are gonna be put in a tough spot after cr if he happens to come over the top of you. Just something to think about.