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 (
    4109, 4032, 4033, 4034, 4035, 4036, 4164, 
    4161, 4162, 4175, 4176, 4177, 4178, 
    4179, 4180, 4181, 4182, 4183, 4184, 
    4185, 4186, 4187, 4188, 4192, 4193, 
    4194, 4195, 4199, 4200, 4201, 4202, 
    4367, 4020, 4021, 4022, 4023, 3934, 
    3932, 3970, 4024, 4014, 4065, 4113, 
    4086, 4089, 4092, 4093, 4097, 4018, 
    4028, 3929, 4052, 4010, 3955, 4150, 
    4151, 4050, 3930, 4189, 4037, 4038, 
    4039, 4040, 4025, 4119, 4126, 4127, 
    4072, 4145, 4146, 4147, 4060, 3974, 
    4041, 4103, 4148, 4102, 4366, 4064, 
    4062, 4101, 4063, 4074, 4075, 4076, 
    4077, 4078, 4079, 4080
  ) 
  AND cscart_discussion.object_type = "P" 
GROUP BY 
  cscart_discussion.object_id

Query time 0.00062

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "table_name": "cscart_discussion",
      "access_type": "range",
      "possible_keys": ["object_id"],
      "key": "object_id",
      "key_length": "6",
      "used_key_parts": ["object_id", "object_type"],
      "rows": 89,
      "filtered": 100,
      "index_condition": "cscart_discussion.object_id in (4109,4032,4033,4034,4035,4036,4164,4161,4162,4175,4176,4177,4178,4179,4180,4181,4182,4183,4184,4185,4186,4187,4188,4192,4193,4194,4195,4199,4200,4201,4202,4367,4020,4021,4022,4023,3934,3932,3970,4024,4014,4065,4113,4086,4089,4092,4093,4097,4018,4028,3929,4052,4010,3955,4150,4151,4050,3930,4189,4037,4038,4039,4040,4025,4119,4126,4127,4072,4145,4146,4147,4060,3974,4041,4103,4148,4102,4366,4064,4062,4101,4063,4074,4075,4076,4077,4078,4079,4080) and cscart_discussion.object_type = 'P'"
    },
    "table": {
      "table_name": "cscart_discussion_posts",
      "access_type": "ref",
      "possible_keys": ["thread_id", "thread_id_2"],
      "key": "thread_id_2",
      "key_length": "6",
      "used_key_parts": ["thread_id", "status"],
      "ref": ["ymonline_livedata.cscart_discussion.thread_id", "const"],
      "rows": 1,
      "filtered": 100,
      "attached_condition": "trigcond(cscart_discussion_posts.`status` = 'A')"
    },
    "table": {
      "table_name": "cscart_discussion_rating",
      "access_type": "eq_ref",
      "possible_keys": ["PRIMARY", "thread_id"],
      "key": "PRIMARY",
      "key_length": "3",
      "used_key_parts": ["post_id"],
      "ref": ["ymonline_livedata.cscart_discussion_posts.post_id"],
      "rows": 1,
      "filtered": 100,
      "attached_condition": "trigcond(cscart_discussion_rating.thread_id = cscart_discussion.thread_id and cscart_discussion_rating.rating_value <> 0 and trigcond(cscart_discussion_posts.post_id is not null))"
    }
  }
}