200NL deep: solid villain pushes for cbet on paired flop

[flow void]

So, villain has done nothing out of line and neither have I. We have been at the table for about 45 minutes and he has 3bet only once before this hand and took it down preflop. He has about 400 in front of him, I cover.

6 handed. I open for 7 with AKo on the button. SB folds and villain makes it 25 from the BB. I call.

Flop comes K J J, rainbow. He pushes about 375 into the 51 dollar pot. Almost instantly. WTF?