Get the page ID with a page template assigned to it
$sql = "select post_id from $wpdb->postmeta where meta_key like '_wp_page_template' and meta_value = 'template-products.php'";
$result = $wpdb->get_results( $sql );
foreach ( $result as $value ) {
$page_id = $value->post_id;
}
wp_reset_query();