Poker Is AK correctly playing KK --or *being played* like a fiddle?

2/5 NL Mohegan Sun

Preflop
MP ($800 stack) opens to $20
Button ($500) raises to $70 with A K
MP calls

Flop
K Q 8
MP checks
Button bets $70
MP calls

Turn
J
MP checks
Button bets $70
MP calls

River
A
MP bets $215

What should button do now? How, if at all, should button have played differently either preflop or on the turn?

Button calls (after 2 min tank)

Can reveal what MP had & offer my own analysis, but curious what others think. Thanks!

Source.