Overcards and backdoor OOP against small raise

GG Poker - $0.50 NL FAST (6 max) - Holdem - 6 players
Hand converted by PokerTracker 4

BTN: 127.2 BB
SB: 258.56 BB
BB: 277.44 BB
Hero (UTG): 114.54 BB
MP: 138.08 BB
CO: 161.9 BB

SB posts SB 0.5 BB, BB posts BB 1 BB

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

Hero raises to 2.5 BB, fold, fold, BTN calls 2.5 BB, fold, fold

Flop: (6.5 BB, 2 players) 4♠ 3♥ Q♥
Hero bets 2.16 BB, BTN raises to 7.58 BB, Hero calls 5.42 BB

Turn: (21.66 BB, 2 players) 2♣
Hero checks, BTN bets 10.84 BB, Hero raises to 35 BB, BTN calls 24.16 BB

River: (91.66 BB, 2 players) Q♦
Hero checks, BTN checks