SELECT 
  state_id 
FROM 
  cscart_states 
WHERE 
  code = 'NIZ' 
  AND country_code = 'RU'

Query time 0.00015

Explain
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE cscart_states const cs,code,country_code cs 106 const,const 1

Result

state_id
574