Is it convenient to ask the journal's editor for two additional days to complete a review?
Getting a review in two days late for a journal article is pretty common. I wouldn't worry about anything less than being a week late. For conferences, deadlines can be tighter, but 2 days is nothing. Ideally you would let the editor know your review will be a couple of days late, but even if you didn't, it is not the end of the world.