Stake: 1-1-2 NL

Lowjack limps ($80 stack - tight/weak)
Button raises to $12 ($900 - tight/aggressive - good player)
Small blind calls ($92 stack - tight/passive)
Hero calls with with J10 ($400 stack)

Flop: J 10 7

Small blind checks
Hero bets $21
Lowjack calls
Button calls
Small blind goes all in for $61 more

Lowjack makes it pretty clear she is going to call by body language so assuming she is has some sort of draw. Button could be on a wide range of hands.

What should I do?

The good player should have raised with a good hand here so you are likely way ahead. Make it like 160 straight

$200.

Pretty ugly situation. If button is actually good they should never have you beat unless button picked up that SB was going to shove. Either of the short bad players could though. I don't like raising because you may just be isolating yourself with opponents that already have you beat and given all of the interest in the pot some of your outs are probably dead. I don't like flatting because your giving way too good of odds to the villains behind you and both are likely drawing to something. I don't like folding top two when it's reasonably likely you have the best hand.

Villains can be on a wide range of hands and you can put them on plausible combinations where you are well ahead (multiple draws that block each other) or way behind (somebody already has you beat and the other two have your outs). Isn't much to do but make a read and go with. Either raise to $200 and commit yourself to the hand or make a tight fold now.