SELECT 
  thread_id, 
  type, 
  object_type 
FROM 
  cscart_discussion 
WHERE 
  1 
  AND object_id = 119 
  AND object_type = 'A' 
  AND cscart_discussion.company_id = 1

Query time 0.00019

Explain
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE cscart_discussion const object_id,company_id object_id 10 const,const,const 1

Result

thread_id type object_type
8525 C A