Your [key_buffer_size][1] is way too big.

Since your MyISAM indexes is that small, set it to 128K.

You need to open my.cnf and add this under the `[mysqld]` group header

    [mysqld]
    key_buffer_size = 128K;

You don't need to restart mysql. Just run this

    SET GLOBAL key_buffer_size = 1024 * 128;

Give it a Try !!!

  [1]: http://dev.mysql.com/doc/refman/5.6/en/server-system-variables.html#sysvar_key_buffer_size