Find MySQL InnoDB index corruption

I have large MySQL InnoDB table on my localhost. In this table primary key is id, unique index is set on fields a, b, c. When I run query: SELECT * FROM mytable WHERE a = 1 AND b = 2 AND c = 3; the result is empty set, but such row certainly exists in the table. When I add " AND id = 1234" at the end (where 1234 is id of expected result): SELECT * FROM mytable WHERE a = 1 AND b = 2 AND c = 3 AND id = 1234; it returns 1 row, as expected. The only explanation is that unique index is corrupted. But when I tried to check table with: mysqlcheck -c mydb mytable or with: ANALYZE table mydb.mytable; both checks returned OK with no errors. So the question is: How to identify this error in index? Is there a way to find this error with some query? MySQL version is 5.7.23, in error.log no errrors. ---------- **Edit:** It turned out, that after creating empty table mytable1 with same structure and filling it with data by query: INSERT INTO mytable1 (SELECT * FROM mytable); this error is present in mytable1, which is impossible in case of index curruption. After some research I have found, that the trouble is in field c, which has timestamp type. Actual table structure is: CREATE TABLE mytable ( id int(10) unsigned NOT NULL AUTO_INCREMENT, a int(10) unsigned NOT NULL, b int(10) unsigned NOT NULL, c timestamp NOT NULL DEFAULT '1999-01-01 00:00:00', d tinyint(1) NOT NULL DEFAULT '0', created timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP, updated timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP, PRIMARY KEY (id), UNIQUE KEY index2 (a,b,c,d) ) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci; There are screenshots of mysql queries: Third query differs from first by 'LIKE' instead of '=' I don't know the reason why first query returned empty set, it looks like some bug in MySQL related with timestamp field. I run query, which fixed this error: UPDATE mytable SET c = FROM_UNIXTIME(UNIX_TIMESTAMP(c)); After this update the problem query began work fine. But actually, this update must do nothing. ---------- **Edit 2** I have found, that the cause of this problem is in clock change in Russia on October 26, 2014. Because my local setting were: mysql> select @@global.time_zone, @@session.time_zone; SYSTEM | SYSTEM so on my localhost datetime '2014-10-26 01:00:00' had two timestamps: mysql> select from_unixtime(1414270800); 2014-10-26 01:00:00 mysql> select from_unixtime(1414274400); 2014-10-26 01:00:00 So select by value returned empty set: mysql> select * from test_db.mytable where c = '2014-10-26 01:00:00'; Empty set but select by id returned correct data: mysql> select c from test_db.mytable where id = 316572297; 2014-10-26 01:00:00 I have changed default-time-zone in my.cnf to '+03:00', and everything began work fine. Note: to reproduce error you must also have index on field c. Without it select by value c = ... works fine.