NL50 - KK overpair gets 3-bet on the flop

[Triggerle]

Standard lay-down?

Full Tilt Poker
No Limit Holdem Ring game
Blinds: $0.25/$0.50
6 players
Converter

Stack sizes:
UTG: $52.85
UTG+1: $65
CO: $23.50
Hero: $49.25
SB: $66.95
BB: $58.05

Pre-flop: (6 players) Hero is Button with K[img]/images/graemlins/spade.gif[/img] K[img]/images/graemlins/diamond.gif[/img]
UTG calls, 2 folds, <font color="#cc0000">Hero raises to $2</font>, SB calls, 2 folds.

Flop: 2[img]/images/graemlins/diamond.gif[/img] 6[img]/images/graemlins/heart.gif[/img] 4[img]/images/graemlins/heart.gif[/img] ($5, 2 players)
<font color="#cc0000">SB bets $5</font>, <font color="#cc0000">Hero raises to $15</font>, <font color="#cc0000">SB raises all-in $64.95</font>, Hero ??