Transaction problem

[Dott. Christian OLIVIERI]

Hi, I'm a newbie and the following is my problem:  I have a db MySQL 
managing personal information. That I would do is: everyone can READ 
single record. If someone open the record x to update/delete no one 
other can do the same (edit/update) till first user don't commit.

I was thinking Local Transaction was the answer but if user A open a 
record in update then user B open the same record, B is hanged untill 
timeout ends.

How to alter timeout value?

Thanks a lot.
Christian