No one knows if the key break will take minutes, hours, weeks, years but I suppose it won't be one entity takes it all with a single attack in a single day.
Well, it's very unlikely its going to be quick, i.e a few minutes. Besides, you'll have a gradual build up to this. We aren't anywhere near the capability of doing it right now, and even when you factor in exponential growth there's going to be a long, long time before something is capable of doing it within minutes.