Ever not beat here?

[Saien]

This is a live game, so no easy hand history:

Me on Button: $500
BB: $600

Game is a California special: 2-3-5 Spread Limit, $10 to see the flop. That's $2 on button, $3 on sb, $5 on BB, a limp is $10. $200 max bet or raise.

Two limpers before me, I have AKo, raise to $40, sb mucks, BB raises $60 to $100 total. Both limpers muck. I call planning to muck if no A or K, not intending to bluff. Opponent is reasonable player who certainly can bluff.

Flop comes AT3 rainbow. I check, BB bets $100, I raise $200. Opponent pushes me all in.

Am I ever ahead here? Do I call anyways because there's $900 in the pot? I'm 15% against AT or 3% against TT/33.