'In future After' and 'In future' condition: how works in the smart list and Mytoken

The StartDateTime value is like 2021-04-06 17:00:00 in Marketo.
I want to fetch the records for 6th Day.
Does is calculate with date and Time both or only for Date difference for any of the future records
How does condition work For DateTime data type custom field in the Smart list?
And if I want to add the same condition in the Velocity Script of the Mytoken to fetch the Meeting date in the email content, How can I write the script?