бронь на сайте сохраняется несколько часов, 6-7 (не помню точно)
Из FAQ с сабжевого сайта:
The time you have to make the payment of a reservation depends on the archaeological site to visit:
Inca Trail: Two and half hours to make payment.
Machupicchu: The reservation is valid only for 6 hours (after 6 hours your reservation is canceled or deleted).
Other Archaeological Center: Five hours to make payment.
At the end of this time the system gives the reservation canceled.
Перевод, надеюсь, не требуется?