This is pretty vague. You should give the whole concept of the puzzle so we can possibly do the whole Event System for you or just help you through it.
I'm a crappy eventer and I haven't evented in ages, but let's see if this is satisfactory.
Off this information...How about you make a Parallel Process Event?
Have two variables that records the player's coordinates. The player can only press these certain buttons when s/he is in front of the statue, yes? If so, then there's a certain coordinate there the player has to be on. Let's say one of these spaces are 3,5. Get the Parallel Process Event to record these coordinates (Variable Operation).
This can be achieved with Condtional Branches asking "Is Variable 001: X = 3" and "Is Variable 002: Y = 5"? Now, once these conditions are met, let's go into yet another Conditional Branch. This Branch will be "Is 'Button' being pressed". Ah-ha. Now once that is pressed, just have the door open. This works easily when there's multiple doors around though...I can't think of anything at the moment for a single door.
(Well, I can, but it's going to require switches and that's not cool)
EDIT: If you want a DIRECT KEY to be pressed, such as something directly on the keyboard (And not an RMXP Key), then you will need a custom script for that.