How to speed up query containing concat() in WHERE clause?
Since your situation is


product is commercial
you cannot change the query
you cannot change table layout


Your best shot (really your only shot) would be

ALTER TABLE table2 ADD INDEX status_table1_ndx (status,table1);


You may or may not see a change since the 

AND table2.table1 = CONCAT( 'constant prefix', table1.attrib1 )


is really a JOIN clause due to having the two tables on opposite sides of the = sign. The CONCAT on the right side would also trigger a full table scan. Adding the compound index on status and table1 seems to be the only option left.