Almost Too Late (Right On Time)

How can I open this cupboard?
Please, will someone assist?
The dust has sealed all it's edges
and my attempts, it seems to resist.

What method must I use on this cupboard
to break it's stubborn stick?
It is imperative I reach it's contents,
for from within I hear a faint tick.

Why, might I ask, does this cupboard
hold it's permanent shut?
I have tried to weaken it's borders,
lined with soot and smut.

What's this, that lies by the cupboard?-
A key that just may fit...
Oh, look at what's held in the cupboard!
My heart has almost quit.