Same as mine...
The strange thing is: Your query doesn't use the index for SE. And I think because of that a temp table is also created and that's the reason it is so slow...
Code:
+------+--------------------+-------+--------+---------------+---------+---------+-------------------------+-------+--------------------------+
| id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra |
+------+--------------------+-------+--------+---------------+---------+---------+-------------------------+-------+--------------------------+
| 1 | PRIMARY | SE | eq_ref | PRIMARY | PRIMARY | 4 | sourcebans.BA.sid | 1 | <- mine |
| 1 | PRIMARY | SE | ALL | PRIMARY | NULL | NULL | NULL | 4 | <- yours |
EDIT:
Here is my "Data dictionary" (ignore bans2)
Maybe you can spot something...
The main difference I see is that the Cardinality for reason & authid_2 in sb_bans is = the Card. of PRIMARY. Whereas in your screenshot it's much smaller.