Opponent unknown. I considered checking behind on the turn, but wanted to avoid seeing a fourth heart.

PokerStars No-Limit Hold'em, $2 BB (5 handed) Hand History Converter Tool from FlopTurnRiver.com (Format: FlopTurnRiver)

saw flop|saw showdown

SB ($222.05)
BB ($249.85)
UTG ($199.60)
Hero ($191)
Button ($163.75)

Preflop: Hero is MP with Q, K.
UTG calls $2, Hero raises to $8, 3 folds, UTG calls $6.

Flop: ($19) 7, 3, Q (2 players)
UTG checks, Hero bets $12, UTG calls $12.

Turn: ($43) K (2 players)
UTG checks, Hero bets $24, UTG raises to $48, Hero calls $24.

River: ($139) 5 (2 players)
UTG checks, Hero bets $123 (All-In)