Unwashed unfertilised eggs can last a year in pretty much room temperature. (If they aren't damaged in any way at all, which is something that even washing them does.)
But the "best before" day is even then set at the shortest date possible in case one of the eggs is a bit damaged, since that's how long they dare to promise that "it'll be fine, it'll be fine".
(After that there's always the risk that one of them might have spoiled - that's why old cooking manuals tell you to crack the eggs first one by one into a separate container, so you can just discard any bad eggs without loosing the entire dish/cake).