SELECT 
  cscart_discussion.object_id AS product_id, 
  AVG(
    cscart_discussion_rating.rating_value
  ) AS average_rating, 
  cscart_discussion.type AS discussion_type, 
  cscart_discussion.thread_id AS discussion_thread_id 
FROM 
  cscart_discussion 
  LEFT JOIN cscart_discussion_posts ON cscart_discussion_posts.thread_id = cscart_discussion.thread_id 
  AND cscart_discussion_posts.status = "A" 
  LEFT JOIN cscart_discussion_rating ON cscart_discussion.thread_id = cscart_discussion_rating.thread_id 
  AND cscart_discussion_rating.post_id = cscart_discussion_posts.post_id 
  AND cscart_discussion_rating.rating_value != 0 
WHERE 
  cscart_discussion.object_id IN (
    9861, 3520, 580, 8347, 1167, 3246, 1162, 
    1196, 1193, 1628, 583, 1159
  ) 
  AND cscart_discussion.object_type = "P" 
  AND cscart_discussion.company_id = 2 
GROUP BY 
  cscart_discussion.object_id

Query time 0.00047

Explain
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE cscart_discussion range object_id,company_id object_id 10 12 Using index condition
1 SIMPLE cscart_discussion_posts ref thread_id,thread_id_2 thread_id 3 mahm3t_cs443.cscart_discussion.thread_id 4 Using where
1 SIMPLE cscart_discussion_rating eq_ref PRIMARY,thread_id PRIMARY 3 mahm3t_cs443.cscart_discussion_posts.post_id 1 Using where

Result

product_id average_rating discussion_type discussion_thread_id
580 B 244
583 B 247
1159 B 875
1162 B 874
1167 B 880
1193 B 909
1196 D 912
1628 B 926
3246 B 995
3520 B 1017
8347 B 1077
9861 D 3246