Is there anyway to improve query
The query might also have been compiled for different parameter values than were used in this execution. Compare the plan with the one you get if you add the query hint OPTION (RECOMPILE). If it is much better, you probably have a parameter-sensitivity problem.
You could also consider adding "Column32" from the Key Lookup as an included column to Index8 on Table4. There may be other things to address as well, but those are the first things I would look into.