Here's a rule to learn and live by... Big Little is Big Trouble. A5, K3 etc. It's worse than 67 or 78. Here's why. If you flop top pair you have a horrible kicker. If you flop bottom pair, big deal. What makes it such a bad hand isn't the preflop call, it's the trouble you get into post flop if you hit a piece. These type hands will lose lots of money compared to 67 where you'll immediately get out if you don't make 2 pair or a straight draw. See what I'm saying here? If you're thinking, "what if I hit 2 pair or the low trips?" then you need to get some poker therapy. That's the excuse for playing Any 2 cards. The fact that one of them is a K or A is irrelevant.

Good luck! and happy playing.