Murata is also a pressure fighter which both of them are. He isn't really a big contender here, I could say Golovkin isn't cherry-picking after all he is 39 and then matched to a boxer that could be considered inexperienced base on the number of fights.
There's no time for Golovkin to cherry pick his opponent, now he is facing a champion as well in the MW division although others say Murata lacks experience, I doubt that is the case. He also fought a lot of good MW.
Golovkin also gives a favorable venue for Murata since this is going to be held in Japan. If GG couldn't make a big difference such as knocking Murata down, he'll not get the win. If the fight will be too close, it's Murata still. No draw here.
I will go with Golovkin here, I think he is the heavier puncher between the two. Murata is good no doubt and has a good chin, but Gennady still possesses that knock out power even body punch.