Checking if the current date and time is past a certain date time in PHP can be done easily with the built-in PHP DateTime class.

This ensures that a date time string is parsed and formatted correctly to have an accurate comparison.

<?php
$date_var = '2020-04-19 10:34:55';
if (new DateTime() > new DateTime($date_var)) {
    //current date time has passed $date_var

} else {
    //current date time has NOT passed $date_var

}

new DateTime()

Is the current date time for the set PHP timezone. Whilst $date_var can be hardcoded or pulled from a database. It also doesn’t have to be full Y-m-d H:i:s you can compare to a day or month, the full format is just really defined.

You can also substitute  new DateTime() for a set date time rather than the current.