Wird der Index durch MySQL ungültig?

mysql> desc wähle * aus tb_province, wobei Name in ('lily3', 'lily2', 'lily1');
+----+----------+-------------+------------+------+---------------+---------+---------+---------+---------+---------+----------+----------+-------------+
| ID | Auswahltyp | Tabelle | Partitionen | Typ | mögliche Schlüssel | Schlüssel | Schlüssellänge | Ref. | Zeilen | gefiltert | Extra |
+----+----------+-------------+------------+------+---------------+---------+---------+---------+---------+---------+----------+----------+-------------+
| 1 | SIMPLE | tb_province | NULL | ALLE | NULL | NULL | NULL | NULL | 108780 | 30,00 | Verwenden von „where“ |
+----+----------+-------------+------------+------+---------------+---------+---------+---------+---------+---------+----------+----------+-------------+
1 Zeile im Satz, 1 Warnung (0,00 Sek.)

mysql> Tabelle tb_province ändern, Index g(Name) hinzufügen;
Abfrage OK, 0 Zeilen betroffen (0,29 Sek.)
Datensätze: 0 Duplikate: 0 Warnungen: 0

mysql> desc wähle * aus tb_province, wobei Name in ('lily3', 'lily2', 'lily1');
+----+----------+-------------+------------+-------+---------------+---------+---------+------+---------+------+---------+------+----------+----------+----------+----------+-----------+
| ID | Auswahltyp | Tabelle | Partitionen | Typ | mögliche Schlüssel | Schlüssel | Schlüssellänge | Ref. | Zeilen | gefiltert | Extra |
+----+----------+-------------+------------+-------+---------------+---------+---------+------+---------+------+---------+------+----------+----------+----------+----------+-----------+
| 1 | SIMPLE | tb_province | NULL | Bereich | g | g | 34 | NULL | 3 | 100,00 | Indexbedingung wird verwendet |
+----+----------+-------------+------------+-------+---------------+---------+---------+------+---------+------+---------+------+----------+----------+----------+----------+-----------+
1 Zeile im Satz, 1 Warnung (0,00 Sek.)
MySQL>

mysql> wähle * aus tb_province, wobei Name in ('lily3', 'lily2', 'lily1');
+----+-------+-------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+
| ID | Name | Punktzahl | x | x1 | x2 | x3 | x4 | x5 | x6 | x7 | x8 | x9 | x10 |
+----+-------+-------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+
| 1 | lily1 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| 2 | lily2 | 2 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| 3 | lily3 | 3 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
+----+-------+-------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+------+
3 Zeilen im Satz (0,00 Sek.)
MySQL>