Quick code to check whether your string is a date. You can specify an input format.
function isThisADate($date, $format = 'Y-m-d H:i:s') { return (DateTime::createFromFormat($format, $date) !== FALSE) ? true : false; }
$date = '2017-10-500 10:11:12'; var_dump(isThisADate($date)); bool(false)