Hi Tabea
I assume you do have SMMJ in production but maybe not a business role & user configured against is so you can use it.
SAP support will request this and it's the easiest way to test if the standard transaction type has the same problem which would point out a coding bug exists most likely.
A technical person can take a look at that table and table access ~SCTS_TRACK to see if it can be optimized.
In terms of the timeout, you don't get any dumps or messages or anything in the system when you check ST22, SLG1 for example?
I don't know if this parameter has an effect on that timing but you try out parameter CHECK_NTIMES_SOCM - Change Request Management scenario: Usual questions and known errors
Kind regards
Tom