Woocommerce products search with custom fields

usually i’m typing a barcode or an sku number. so i’m fetching 1 result. when i’m not using this script the search results are taking about 2-3 seconds.
this is my script:

function cf_search_join( $join ) {
    global $wpdb;

    if ( is_search() ) {    
        $join .=' LEFT JOIN '.$wpdb->postmeta. ' ON '. $wpdb->posts . '.ID = ' . $wpdb->postmeta . '.post_id ';
    }
    return $join;
}
add_filter('posts_join', 'cf_search_join');

function cf_search_where( $where ) {
    global $pagenow, $wpdb;

    if ( is_search() ) {
        $where = preg_replace(
          "/\(\s*".$wpdb->posts.".post_title\s+LIKE\s*(\'[^\']+\')\s*\)/",
          "(".$wpdb->posts.".post_title LIKE $1 OR ".$wpdb->posts.".post_excerpt LIKE $1) OR (".$wpdb->postmeta. ".meta_value LIKE $1 AND ".$wpdb->postmeta. ".meta_key IN ('_barcode','_sku') )", $where );
    }

    return $where;
}
add_filter('posts_where', 'cf_search_where');

function cf_search_distinct( $where ) {
    global $wpdb;

    if ( is_search() ) {
        return "DISTINCT";
    }

    return $where;
}
add_filter( 'posts_distinct', 'cf_search_distinct' );