Specify the hour of the day that the Shield Security plugin executes its daily cron

functions.php

<?php
/**
 * The Scanner cron job run by the Shield plugin is responsible for executing the scans.
 * If you're running ShieldFREE, the scans runs automatically once per day. On ShieldPRO, it can repeat up to every hour.
 *
 * The Cron is configured to have a start time - i.e. the first time that the cron will execute. Then it repeats based on your settings.
 *
 * If the hour at which the cron is set to run is 3 a.m. (the default), it will first run the next day at 3am, and then
 * every day thereafter at 3 a.m.  If this default hour doesn't suit, you can change it using a WordPress filter.
 *
 * The following example will change the hour to 5 a.m. instead of the default, 3 a.m.
 * 
 * Note: The hour is 24hr notation, so 5 a.m. is '5', and 5 p.m. is '17'.
 * 
 * Note: Shield crons are reset/setup at instant the plugin is upgraded/activated - ensure that this filter is in-place beforehand so your preferences are applied.
 */
add_filter( 'shield/scan_cron_start_hour', function ( $hour ) {
	return 5;
} );