Filesort
+- TEMPORARY
   table          temporary(log,user,emailtemplate)
   +- JOIN
      +- Join buffer
      |  +- Filter with WHERE
      |     +- Table scan
      |        rows           17
      |        +- Table
      |           table          emailtemplate
      +- JOIN
         +- Bookmark lookup
         |  +- Table
         |  |  table          user
         |  |  possible_keys  PRIMARY
         |  +- Unique index lookup
         |     key            user->PRIMARY
         |     possible_keys  PRIMARY
         |     key_len        4
         |     ref            waca_production.log.user
         |     rows           1
         +- Index scan
            key            log->log_idx_typeuseraction
            possible_keys  log_idx_action,log_idx_user
            key_len        908
            rows           351102