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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 (
    68835, 69400, 69349, 69324, 69291, 69257, 
    69256, 69255, 69123, 68831, 68697, 
    68696, 68879, 68906, 68576, 69176, 
    69175, 69174, 69033, 67842, 69173, 
    69172, 69100, 69099, 69032, 69022, 
    68905, 68408, 68368, 68367, 68695, 
    68547, 68555, 68904, 68903, 68834, 
    68833, 68725, 68605, 68292
  )

Query time 0.00026

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