Custom cron script for WP

cron.php

<?php

// This code can go anywhere as long as its loaded by a plugin or theme

// setup the schedual
if ( ! wp_next_scheduled( 'my_task_hook' ) ) {
  wp_schedule_event( time(), 'hourly', 'my_task_hook' );
}

add_action( 'my_task_hook', 'my_task_function' );

/**
 * Function to run the cron
 *
 * @author         Jeff Behnke <code@validwebs.com>
 * @copyright  (c) 2009-15 ValidWebs.com
 *
 * Created:    7/1/16, 11:22 AM
 *
 */
function my_task_function() {
	// CHANGE this url to match your file URL
	$url  = 'http://site.com/path/to/custom-cron.php';
	$key  = md5( 'test' );

	$response = wp_remote_post( $url, array(
			'method'      => 'POST',
			'timeout'     => 45,
			'redirection' => 5,
			'httpversion' => '1.0',
			'blocking'    => true,
			'headers'     => array(),
			'body'        => array( 'key' => $key ),
			'cookies'     => array()
		)
	);

	if ( is_wp_error( $response ) ) {
		$error_message = $response->get_error_message();
		echo "Something went wrong: $error_message";
	} else {
		echo 'Response:<pre>';
		print_r( $response );
		echo '</pre>';
	}

}

custom-cron.php

<?php

// This is a bin type script and gets run from cron or other service

// Don't load themes
define( 'WP_USE_THEMES', false );
// replace path/to
require( 'path/to/wp-blog-header.php' );

$key = md5( 'test' );

// do some verification to make sure you want this to run and a bot is not hitting it none stop]
if ( isset( $_POST['key'] ) && $_POST['key'] == $key ) {
	// if verify passes
	header( "HTTP/1.1 200 OK" );

	// The code  you want to run here


  die();
} else {
	
	header( "HTTP/1.1 401 Unauthorized" );
	die( '401 Unauthorized' );
}