While it is not certain, it is very possible and indeed quite likely that they may have a look at it.

Do you really care about the sealed box? If not, you could slip it inside a pocket of yours and then discretely put it back in the box/gift bag after you are past security (weird thing to do in the CCR bathrooms but why not I guess! ). Typically, I'm never asked to show phones in my pockets and almost often when they are in my bags!