I've put this code to my wordpress functions.php file. But this code works after any page reload on my site and sends sms. what is the problem? How can I understand daily scheduled event is set or not?

if (!wp_next_scheduled('daily_send_sms_hook')) {
    wp_schedule_event(time(), 'daily', 'daily_send_sms_hook');
}
add_action('daily_send_sms_hook', 'daily_send_sms');

function daily_send_sms() {
    // send sms code
}