3/5 live game at the Morongo - tough pre-flop decision

[FreakDaddy]

UTG+1 ~$450
MP1 ~$150
Hero covers on button

UTG+1 is a decently solid player, but he's quite tight. Haven't seen him get out of line and he's not played a lot of pots. He open for 6xBB which 5-6 is standard.

Folds to MP1 who is a bit fishy and plays a lot of hands and he pushes.

Folds to me on button and I look down at R&B Kings.

What's my play?
Here's my thought process:
UTG+1 is fairly tight and for him to open 6x in EP I know he has a very solid hand. His range to me is AK,AA,QQ and probably not even JJ or AQ, although they are still a remote possibility.
MP1's range is much higher and he could have all the standard including AA-TT, AK, AQ and even AJs is a remote possibility.
I can very likely have MP1 beat. If I push UTG+1 is folding everything except AA in my mind. I can't flat call here. So do I just close my eyes and push, or just wait for another spot?

Results to follow.