add indexes as part of temp table definition on mysql

prevents committing the transaction

Change-Id: I07ed52a07a4ec8ebae783b052f6e864c89fd5947
Reviewed-on: https://gerrit.instructure.com/29023
Tested-by: Jenkins <jenkins@instructure.com>
Reviewed-by: Nick Cloward <ncloward@instructure.com>
QA-Review: Cody Cutrer <cody@instructure.com>
Product-Review: Cody Cutrer <cody@instructure.com>