Setup crons

<?php
    /*
    Plugin Name: Manage Crons
    Version: 1.0
    Description: This plugin handles (some) cron jobs.
    Author: Aseda
    Author URI: https://aseda.nl

    http://www.berryplasman.com
       ___  ____ ____ ____
      / _ )/ __/  __/  __/
     / _  / _/   _/   _/
    /____/___/____/____/

    */

    if ( ! defined( 'ABSPATH' ) ) {
        exit; // Exit if accessed directly
    }

    if ( ! class_exists( 'Sd8Crons' ) ) :

        /**
         * Main class
         */
        class Sd8Crons {

            var $settings;

            /**
             *  A dummy constructor to ensure plugin is only initialized once
             */
            public function __construct() {
            }

            public function initialize() {
                $this->settings = [
                    'path'    => trailingslashit( dirname( __FILE__ ) ),
                    'version' => '1.0',
                ];

                register_activation_hook( __FILE__,     [ $this, 'plugin_activation' ] );
                register_deactivation_hook( __FILE__,   [ $this, 'plugin_deactivation' ] );

                add_action( 'sd_expire_orders',             [ $this, 'sd_expire_orders' ] );

                add_filter( 'cron_schedules',               [ $this, 'sd_cron_schedules' ] );
            }


            public function plugin_activation() {
                if ( ! wp_next_scheduled( 'sd_expire_orders' ) ) {
                    wp_schedule_event( time(), 'every_5_min', 'sd_expire_orders' );
                }
            }


            public function plugin_deactivation() {
                $timestamp = wp_next_scheduled( 'sd_expire_orders' );
                wp_unschedule_event( $timestamp, 'sd_expire_orders' );
            }


            public function sd_cron_schedules( $cron_schedules ) {
                if ( ! array_key_exists( 'every_5_min', $cron_schedules ) ) {
                    $cron_schedules[ 'every_5_min' ] = array(
                        'interval' => 5 * MINUTE_IN_SECONDS,
                        'display'  => __( 'Every 5 min' ),
                    );
                }

                return $cron_schedules;
            }


            /**
             * Expire orders if not paid
             *
             * @return void
             */
            public function sd_expire_orders() {
                if ( function_exists( 'sd_get_unpaid_orders' ) ) {
                    $unpaid_orders = sd_get_unpaid_orders();
                    if ( ! empty( $unpaid_orders ) ) {
                        foreach( $unpaid_orders as $order ) {
                            $order_time = (int) $order->order_time;
                            $expiry     = 'bankwire' == $order->payment_method ? 7 * DAY_IN_SECONDS : 10 * MINUTE_IN_SECONDS;
                            $expire_on  = $order_time + $expiry;

                            if ( $expire_on < sd_get_local_date_time( time(), 'U' ) ) {
                                global $wpdb;
                                $table = $wpdb->prefix . 'orders';
                                $data  = [ 'order_status' => 'expired' ];
                                $where = [ 'id' => $order->id ];
                                $wpdb->update( $table, $data, $where );
                            }
                        }
                    }
                }
            }
        }


        /**
         * The main function responsible for returning the one true Sd8Crons instance to functions everywhere.
         *
         * @return \Sd8Crons
         */
        function init_crons_plugin() {
            global $crons_plugin;

            if ( ! isset( $crons_plugin ) ) {
                $crons_plugin = new Sd8Crons();
                $crons_plugin->initialize();
            }

            return $crons_plugin;
        }

        // initialize
        init_crons_plugin();

    endif; // class_exists check