Is the following index is good? What is the proper indexing plan for the below query?
Query 1 :
select id 
from room_participants 
where roomId=1 
  and userId=1 
  and status=1 
  and isMuted=0

Query 2 :
select group_concat(b.phone) 
from room_participants as a 
left join users as b on b.id=a.userId 
where a.roomId = 1 
  and a.status = 1

Is it an advisable way to do indexing as per my example below? Does this is what we called redundant index as index combine3 is having the same column as index combine4 and index combine2 is having the same column as index combine1?
CREATE TABLE `room_participants` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `roomId` int(11) NOT NULL,
  `userId` int(11) NOT NULL,
  `isAdmin` tinyint(1) DEFAULT '0',
  `isMuted` tinyint(1) NOT NULL DEFAULT '0',
  `joinTime` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP,
  `leftTime` timestamp NULL DEFAULT NULL,
  `kickTime` timestamp NULL DEFAULT NULL,
  `status` tinyint(1) NOT NULL DEFAULT '1' COMMENT '1=join, 2=kicked, 3=left',
  PRIMARY KEY (`id`),
  KEY `userId` (`userId`),
  KEY `combine2` (`isAdmin`,`userId`,`joinTime`,`leftTime`,`kickTime`,`status`),
  KEY `combine1` (`kickTime`,`userId`),
  KEY `combine3` (`roomId`,`userId`,`status`,`isMuted`),
  KEY `combine4` (`roomId`,`status`)
) ENGINE=InnoDB AUTO_INCREMENT=567 DEFAULT CHARSET=latin1;

Please guide me on this. Thanks.
Optimal for both queries:
INDEX(roomId, status,   -- first, in either order
      userId,           -- 3rd
      isMuted)

Notes:

In InnoDB, the PRIMARY KEY is tacked onto the end of each secondary index (so it can get to the record).
All 5 columns (including id) are in that index, so it is &quot;covering&quot; for the first query.
In both queries, the tests in the WHERE clause are completely handled by the first few columns.
In the 2nd query, userId is available, so the index is covering for that query, too.  (The extra isMuted` is not harmful.)
I assume that id is the PK of b, so that is optimal, too.
If you add my index, drop combine4.  (The left part exactly matches.)
More:  http://mysql.rjweb.org/doc.php/index_cookbook_mysql