Locksmith service is provided by municipal organizations called PREO and REU which provide a variety of repair services such as plumbing, electrical, redecorating in addition to locksmithing to their assigned region of the city. See APARTMENT REPAIRS on how to get service. Now many other organizations and private cooperatives providing such services as well.
Many doors have two or more locks. Keys can also be cut in "Metal Repair Shops" (Remont metalloizdeliy).
See METAL REPAIR SHOPS. Good solid doors installed by locksmiths are highly recommended, especially on the first floor along with metal window grills (Reshetki). See ALARM SYSTEMS & SECURITY DEVICES - METAL DOORS, WINDOW GRATES, LOCKS.