let's test one by one.
for
enable rewrite log level 9, my test shows:
RewriteRule ^tovary\.php - [R=410,L]
2013-07-27 21:34:00.865 [INFO] [192.168.2.125:53459-0#Example] [REWRITE] Cond: Match 'a=1&group_1=&b=2' with pattern 'group_1=&', result: 1
2013-07-27 21:34:00.865 [INFO]...