You need to convert it in Coordinated Universal Time format (HH:MM:SS). For example, 10:00PM should become 22:00:00.
From the manual:
MySQL retrieves and displays TIME values in 'HH:MM:SS' format (or 'HHH:MM:SS' format for large hours values). TIME values may range from '-838:59:59' to '838:59:59'. The hours part may be so large because the TIME type can be used not only to represent a time of day (which must be less than 24 hours), but also elapsed time or a time interval between two events (which may be much greater than 24 hours, or even negative).
To convert one time format into another in PHP is fairly easy:
$datetime = DateTime::createFromFormat('h:i A', '10:00 PM');
$time = $datetime->format('H:i:s');