Sandbox

SELECT 
  p.product_id, 
  ifnull(
    count(dp.post_id), 
    0
  ) as discussion_amount_posts 
FROM 
  cscart_discussion 
  INNER JOIN cscart_products as p ON (
    cscart_discussion.object_id = p.product_id
  ) 
  INNER JOIN cscart_discussion_posts as dp ON (
    cscart_discussion.thread_id = dp.thread_id 
    AND cscart_discussion.object_type = 'P' 
    AND cscart_discussion.company_id = 1
  ) 
WHERE 
  dp.status = 'A' 
  and p.product_id in (
    130, 51106, 51107, 51112, 51111, 51110, 
    51109, 51108, 128, 51118, 51117, 51116, 
    51115, 51114, 51113, 51123, 51122, 
    51121, 92, 49, 51129, 51128, 51127, 
    51126, 51125, 48, 51132, 51131, 51134, 
    51133, 51130, 41, 51139, 51138, 51137, 
    51136, 51135, 40, 51144, 51143, 51142, 
    51141, 51140, 39, 51146, 51145, 38, 
    51148, 51147, 51150, 51149, 37, 51155, 
    51154, 51153, 51152, 21, 51158, 51157, 
    51156, 53, 51160, 51159, 50984, 51450, 
    51451, 51329, 51328, 51327, 50985, 
    51331, 51330, 50986, 51332, 51339, 
    51338, 51337, 51336, 50988, 134, 51565, 
    51574, 51575, 51576, 51577, 51567, 
    51582, 51583, 51584, 51585, 51586
  ) 
GROUP BY 
  p.product_id

Query time 0.00063

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}