In more detail, index "FDX_spG_NU_QA_V12" does not contain at least one of the columns:
MC.col1 / MC.col2 / MC.col3
If you believe such an index could be helpful enough to this query, you should look at adding (INCLUDEing) the missing column(s) in that index. Then you can re-try the query.
SQL DBA,SQL Server MVP(07, 08, 09) A socialist is someone who will give you the shirt off *someone else's* back.