3-way pre-flop all-in with AK, 400NL

[ludo72]

UTG sat down not long ago. SB is a donkey who I have put on major tilt with a stupid NPND river all-in bluff which succeeded and which I showed to him. I believe his 4-betting handrange includes most pp's and hands which I dominate. UTG should know that SB is a donkey so I'm not sure if he's calling just to trap me or calling because he's scared of me but believes he is ahead of SB.

saw flop|<font color="#C00000">saw showdown</font>

Button ($565.90)
<font color="#C00000">SB ($308.30)</font>
BB ($1968.25)
<font color="#C00000">UTG ($278)</font>
<font color="#C00000">Hero ($563.40)</font>

Preflop: Hero is MP with K[img]/images/graemlins/heart.gif[/img], A[img]/images/graemlins/diamond.gif[/img]. SB posts a blind of $2.
<font color="#C00000">UTG raises to $15, Hero raises to $45</font>, 1 fold, <font color="#C00000">SB raises to 123$</font>, 1 fold, UTG calls, Hero ??