So I flopped top pair but on this board wasn't sure what to do. How would you play it?

PokerStars No-Limit Hold'em, $0.02 BB (8 handed) Hand History Converter Tool from FlopTurnRiver.com (Format: FlopTurnRiver)

Button ($2.20)
SB ($4.95)
BB ($10.65)
UTG ($1.34)
UTG+1 ($2.06)
MP1 ($2.83)
Hero ($4.98)
CO ($3.03)

Preflop: Hero is MP2 with K, J.
UTG calls $0.02, 1 fold, MP1 calls $0.02, Hero calls $0.02, 1 fold, Button calls $0.02, 1 fold, BB checks.

Flop: ($0.11) 4, J, 3 (5 players)
BB checks, UTG checks, MP1 checks, Hero checks, Button bets $0.1, BB folds, UTG folds, MP1 folds, Hero raises to $0.4, Button folds.

Final Pot: $0.61