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SELECT 
  f.feature_id, 
  f.purpose, 
  p.product_id, 
  p.parent_product_id, 
  g.id, 
  g.code 
FROM 
  cscart_product_variation_group_features AS f 
  INNER JOIN cscart_product_variation_groups AS g ON f.group_id = g.id 
  INNER JOIN cscart_product_variation_group_products AS p ON f.group_id = p.group_id 
WHERE 
  p.product_id IN (
    70121, 70812, 70727, 70339, 70697, 70696, 
    70695, 70694, 70640, 70600, 70584, 
    70539, 70432, 70357, 70587, 70586, 
    70583, 70579, 70537, 70493, 70120, 
    69978, 69977, 70358, 70462, 70459, 
    70458, 70433, 69982, 70435, 70434, 
    70362, 70015, 70014, 70235, 70234, 
    70161, 70119, 69980, 69745
  )

Query time 0.00017

Explain
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	p	ALL	PRIMARY,idx_group_id				376	Using where
1	SIMPLE	g	eq_ref	PRIMARY	PRIMARY	3	toolboxdigitalshop_dev.p.group_id	1
1	SIMPLE	f	ref	idx_group_id	idx_group_id	3	toolboxdigitalshop_dev.p.group_id	7