WordPress - Add custom filers on backend admin post listing

functions.php

/**
 * Add custom filters.
 */
function custom_filters() {

		$post_type = filter_input( INPUT_GET, 'post_type', FILTER_SANITIZE_STRING );

		// Only add filter to post type you want.
		if ( 'POST_TYPE_NAME' === $post_type ) {

			$selected_zone = filter_input( INPUT_GET, 'filter_content_zone', FILTER_SANITIZE_STRING );

			?>
			<select name="filter_content_zone">
				<option value="all"><?php esc_html_e( 'All Content Zones', 'TEXT_DOMAIN' ); ?></option>
				<option value="past" <?php selected( $selected_zone, 'past' ); ?>><?php esc_html_e( 'Past Zones', 'TEXT_DOMAIN' ); ?></option>
				<option value="current" <?php selected( $selected_zone, 'current' ); ?>><?php esc_html_e( 'Current Zones', 'TEXT_DOMAIN' ); ?></option>
				<option value="future" <?php selected( $selected_zone, 'future' ); ?>><?php esc_html_e( 'Future Zones', 'TEXT_DOMAIN' ); ?></option>
			</select>
			<?php
		}
}
add_action( 'restrict_manage_posts', 'custom_filters' );

/**
 * Manage filtering data.
 *
 * @param \WP_Query $query WP_Query object.
 */
function parse_query( $query ) {

		if ( is_admin() && 'POST_TYPE_NAME' === $query->query['post_type'] ) {

			$selected_zone = filter_input( INPUT_GET, 'filter_content_zone', FILTER_SANITIZE_STRING );

			if ( ! empty( $selected_zone ) ) {

				$current_time = time();

				switch ( $selected_zone ) {

					case 'past':
						$query->query_vars['meta_query'] = array(
							array(
								'key'     => '_promo_end_date',
								'value'   => $current_time,
								'compare' => '<',
							),
						);

						break;

					case 'current':
						$query->query_vars['meta_query'] = array(
							array(
								'key'     => '_promo_start_date',
								'value'   => $current_time,
								'compare' => '<',
							),
							array(
								'key'     => '_promo_end_date',
								'value'   => $current_time,
								'compare' => '>',
							),
						);

						break;

					case 'future':
						$query->query_vars['meta_query'] = array(
							array(
								'key'     => '_promo_start_date',
								'value'   => $current_time,
								'compare' => '>',
							),
						);

						break;
				}
			}
		}
}
add_filter( 'parse_query', 'parse_query' );