致命错误：调用未定义的函数NOW（）

Im starting to develop a count viewers online system and Im having a issue. I usually use time(NOW()) to get time but now its giving me this error:

Fatal error: Call to undefined function NOW()

Do you have any ideia why this is happening?

$id_session= $_SESSION['startView']['session'];
if($_SESSION['startView']['time_end'] <= time())
        {
            $delete = $pdo->prepare("DELETE FROM viewers_online WHERE session=? OR time_end <= ? ");
            $delete->bindValue(1,$id_session);  
            $delete->bindValue(2,time(NOW()));
            unset($_SESSION['startView']);  
        }

$delete = $pdo->prepare("DELETE FROM viewers_online WHERE session=? OR time_end <= UNIX_TIMESTAMP(NOW())");
$delete->bindValue(1,$id_session);  
unset($_SESSION['startView']); 

Instead of NOW(), use new DateTime() which is a proper php function. NOW() is a mysql function. Creating a new DateTime() is the equivalent of NOW().