This search feature is available only if time slots and multiple bookings per time period are disabled, please check this in HivePress>Settings>Bookings.
It’s possible for date-based bookings, but if you offer time-based bookings there’s no such option yet - searching availability by time slots is much more complex (since the date becomes not available only if the last time slot is booked, and each listing can have a different time slot duration, allowed start and end booking times) but we plan to implement in future versions.