basically the way i see it the only hand he could possibly have here that would warrant a call is AQ

Yatahay Network - $0.02 NL (6 max) - Holdem - 5 players
Hand converted by PokerTracker 4

UTG: 90 BB
CO: 318 BB
BTN: 100 BB
Hero (SB): 119.5 BB
BB: 56.5 BB

Hero posts SB 0.5 BB, BB posts BB 1 BB

Pre Flop: (pot: 1.5 BB) Hero has K K

UTG raises to 2.5 BB, fold, fold, Hero raises to 8 BB, fold, UTG calls 5.5 BB

Flop: (17 BB, 2 players) Q 3 J
Hero checks, UTG bets 8.5 BB, Hero calls 8.5 BB

Turn: (34 BB, 2 players) 8
Hero checks, UTG bets 25.5 BB

Hero?

I would start with a bet on this flop

nice hand

Why did you check the flop?.... AXX, KXX and QXX is cbet always. And your 3bet is too low you have to 3bet 10bbs out of position vs 2.5bbs cbet

3Bet bigger preflop like 10-11bb.
Bet on the flop. You have an advantage and you don't block calling opponent's range with your hand.

As played - call on the turn.
UTG looks like a fish with a broken stack. So his betting range can be wider than AQ+.
Additionally, there are still numerous draws present on the board.

Fold preflop - they always hit the flop.
If you just call instead of 3bet pre you can fold much cheaper on later streets.

nobody likes creeps

Explain, please, why you 3B to 8bb?

Villain will have lots of lesser combos that call your 3 bet. AQ is one possibility, but there are any number of flush and straight draws he could have; pretty much any Ax dd combo, for example. You flopped well for your holding; certainly he could have QJ, JJ or 33. QQ or JJ should 4! Pre, but this is 2NL and population will often not 4 bet enough. You certainly do not want to give a free card to any of villain’s Ax combos. Getting him to fold such holdings is a good result for you. All this argues for a cbet on the flop. If he does have you beat, you will find out quickly - he likely would raise, especially with a connected two tone flop. His set and two pair combos are likely good, but vulnerable. If he is on a draw, you want to make him pay now; if he misses he won’t pay you off later.

There also are a significant number of players who will read your checks as weakness and bluff based on them. If you have a read on this villain that this is the case, then by all means slow play and trap them, at least in general. However a two tone connected flop is not really the best spot to try to trap; bet this flop and make them pay.

He never explains.