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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 (
    68974, 68973, 68972, 68971, 68970, 68969, 
    68968, 68967, 68966, 68965, 68964, 
    68963, 68962, 68961, 68960, 68959, 
    68958, 68957, 68956, 68955, 68954, 
    68953, 68952, 68951, 68950, 68949, 
    68948, 68947, 68946, 68945, 68321, 
    68290, 68289, 68288, 68286, 68285, 
    68284, 68283, 68282, 68281
  )

Query time 0.00028

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