Tutorial
This is the configuration, where there is defined the rules to leave only wanted dates available.
Twig code for the Min Date
{% if 'now'|date('U') > 'now'|date('Y-m-d 15:30:00')|date('U') %}{{'+2 day'|date('Y-m-d')}}{% else %}{{'+1 day'|date('Y-m-d')}}{% endif %}