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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 (
    15326, 15325, 15324, 15323, 15289, 15290, 
    42114, 42113, 42112, 42111, 15164, 
    15163, 15159, 15132, 15129, 15128, 
    15127, 15162, 15123, 14859, 14857, 
    14856, 14849, 14844, 14836, 14827, 
    14825, 14822, 14817, 14833, 14832, 
    14831, 14830, 14829, 14828, 14826, 
    14824, 14823, 14821, 14820
  )

Query time 0.00023

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