Mysql – How to get only one acl_groups_to_resources.bitmask for a given set of parameters

I have the following tables in my DB:

CREATE TABLE `restricted_components` (
  `component_id` int(11) NOT NULL,
  `resources_id` int(11) NOT NULL,
  `component_dom_id` varchar(50) NOT NULL,
  `component_dom_data_name` varchar(50) DEFAULT NULL,
  PRIMARY KEY (`component_id`),
  UNIQUE KEY `component_id_UNIQUE` (`component_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci;

CREATE TABLE `resources` (
  `resources_id` int(10) unsigned NOT NULL AUTO_INCREMENT,
  `resources_name` varchar(64) COLLATE utf8_unicode_ci NOT NULL,
  `menu_href` varchar(128) COLLATE utf8_unicode_ci DEFAULT NULL,
  `menu_text` varchar(64) COLLATE utf8_unicode_ci NOT NULL,
  PRIMARY KEY (`resources_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci;

CREATE TABLE `acl_groups_to_resources` (
  `groups_id` int(10) unsigned NOT NULL,
  `resources_id` int(10) unsigned NOT NULL,
  `bitmask` smallint(6) NOT NULL DEFAULT '0',
  PRIMARY KEY (`groups_id`,`resources_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci;

CREATE TABLE `groups` (
  `groups_id` int(11) NOT NULL AUTO_INCREMENT,
  `groups_name` varchar(50) COLLATE utf8_unicode_ci NOT NULL,
  PRIMARY KEY (`groups_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci;

CREATE TABLE `users_to_groups` (
  `users_id` int(11) NOT NULL,
  `groups_id` int(11) NOT NULL,
  PRIMARY KEY (`users_id`,`groups_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci;

CREATE TABLE `users` (
  `users_id` int(11) NOT NULL AUTO_INCREMENT,
  `parent_users_id` int(11) DEFAULT '0',
  `firstname` varchar(40) COLLATE utf8_unicode_ci NOT NULL,
  `lastname` varchar(40) COLLATE utf8_unicode_ci NOT NULL,
  `email` varchar(50) COLLATE utf8_unicode_ci NOT NULL,
  `password` varchar(50) COLLATE utf8_unicode_ci DEFAULT NULL,
  PRIMARY KEY (`users_id`),
  UNIQUE KEY `email` (`email`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci;

I need to get the unique acl_groups_to_resources.bitmask value having the restricted_components.component_dom_id, resources.menu_href, users.users_id, [restricted_components.component_dom_data_name] (this last one is optional see the OR on the SQL).

Coming from this post and tweaking it a bit I end up with the following SQL:

SELECT
  `rc`.`component_id`,
  `acl_gr`.`resources_id`,
  `acl_gr`.`bitmask`
FROM `restricted_components` AS `rc`
  LEFT JOIN `resources` AS `rs` ON rc.resources_id = rs.resources_id
  INNER JOIN `acl_groups_to_resources` AS `acl_gr` ON rs.resources_id = acl_gr.resources_id
  INNER JOIN `groups` AS `gr` ON acl_gr.groups_id = gr.groups_id
  INNER JOIN `users_to_groups` AS `usr_gr` ON gr.groups_id = usr_gr.groups_id
  INNER JOIN `users` AS `usr` ON usr_gr.users_id = usr.users_id
WHERE (rc.component_dom_id = 'add_component_restriction')
  AND (rs.menu_href = 'adminconsole')
  AND (usr.users_id = 976)
  OR  (rc.component_dom_data_name = 'btn_add_restriction')

The query above works but I am getting two results instead of one:

component_id | resources_id | bitmask
--------------------------------------
1            | 129          | 1
1            | 129          | 15

A correct output would be a unique row containing the bitmask value for the given parameters. Something is wrong on the query but I am not sure what it's so I need more eyes on this.

This is the current data on each table (maybe the problem is on the data):

restricted_components
=====================

component_id | resources_id | component_dom_id         |  component_dom_data_name
----------------------------------------------------------------------------------
1            | 129          | add_component_restriction  
2            | 129          | edit_component_restriction
3            | 129          | delete_component_restriction

resources
=====================

resources_id | resources_name | menu_href    | menu_text
-------------------------------------------------------------
129          | Add            | adminconsole | Admin Console

acl_groups_to_resources
=====================

groups_id | resources_id | bitmask | created_by_users_id
--------------------------------------------------------
1         | 129          | 1       | 976
2         | 129          | 15      | 976
3         | 129          | 0       | 976

groups
=====================

groups_id | groups_name
---------------------------
1         | Administrators
2         | Restricted Admin
3         | Others

users_to_groups
======================

users_id | groups_id
---------------------------
976      | 1
976      | 2

users
=====================

users_id | parent_users_id | firstname | email
-------------------------------------------------------------
976      | 0               | Dev       | userdev@email.comdev

Can any give me some help on this? (I am using MySQL 5.5)

Note: Feel free to rewrite the SQL if needed in order to obtain the required results.