i dont think he needs a set to beat you. you are out of position on a board with an Ace and all you have is a pair of kings. your hand essentially falls from the monster it was preflop to ... in all likelihood ... a drawing hand that you must play from out of position. very tough spot for you, but after you were raised on the flop, it's obvious that you are behind. i would fold the turn if you dont hit your club or 3rd K.