MySQL - 内部联接需要太长时间

Question

我有一个简单的内连接需要太长时间（在10分钟内停止查询）。它加入了表A和表2的两个表。

使用Describe Command返回以下信息

+--------+---------------+-------------+----------+------+---------+----------------------------------------------+
|  type  | possible_keys |     key     |  key_len |  ref |   rows  |                     extra                    |
+--------+---------------+-------------+----------+------+---------+----------------------------------------------+
| index  | NULL          | myWallet    |       56 | NULL | 4007793 | Using index                                  |
| index  | NULL          | myTransaction|      213| NULL |   45260 | Using where; Using index; Using join buffer  |
+--------+---------------+-------------+----------+------+---------+----------------------------------------------+

Table A 
myTransaction
myWallet
amount

Table B
myWallet
RegistrationDate

SELECT a.myTransaction, a.myWallet, b.RegistrationDate, a.amount 
FROM mytable.tableA a
INNER JOIN mytable.tableB b 
ON a.myWallet = b.myWallet

关于如何加速内部加入的任何建议？