MySQL和嵌套集：慢JOIN（不使用索引）

I have two tables:

我有两张桌子:

localities:

CREATE TABLE `localities` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `name` varchar(100) NOT NULL,
  `type` varchar(30) NOT NULL,
  `parent_id` int(11) DEFAULT NULL,
  `lft` int(11) DEFAULT NULL,
  `rgt` int(11) DEFAULT NULL,
  PRIMARY KEY (`id`),
  KEY `index_localities_on_parent_id_and_type` (`parent_id`,`type`),
  KEY `index_localities_on_name` (`name`),
  KEY `index_localities_on_lft_and_rgt` (`lft`,`rgt`)
) ENGINE=InnoDB;
CR