This can be accomplished by copying only one row to a temporary table:
create temp table saved as select * from config where var_name = 'DBConnectionPool.MaxLifetime' limit 1;
delete from config where var_name = 'DBConnectionPool.MaxLifetime';
insert into config select * from saved;
create temp table saved as select * from config where var_name = 'DBConnectionPool.MaxLifetime' limit 1;
delete from config where var_name = 'DBConnectionPool.MaxLifetime';
insert into config select * from saved;