I couldn't change it to another datastore, i only have one. I just did a new fresh installation of ESXi 6.7.0U1 in a state where i can delete and create a datastore (before it got "locked"). I noticed at that moment the value for keys "ScratchConfig.ConfiguredScratchLocation" and "ScratchConfig.CurrentScratchLocation" was "/tmp/scratch". Those values were changed to "/vmfs/volumes/5c373b88-9c521c6b-8e09-d4ae52e8d640/.locker" (locked state) after creating a datastore and rebooting the system. Remember i am not using vCenter (impossible with free license) or any other type of client. The other thing i dont understand is why ESXi dont let create more than one datastore on my disk.
Thanks...