Sandbox

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 (
    68534, 68533, 68459, 68363, 68362, 68360, 
    68358, 68357, 68135, 68065, 68064, 
    67902, 67896, 67685, 67684, 66983, 
    68359, 67955, 68319, 68312, 67848, 
    67845, 67839, 67686, 67683, 66841, 
    66840, 66839, 67958, 68200, 67770, 
    67769, 67768, 67767, 67766, 67765, 
    67764, 67763, 67762, 67761
  )

Query time 0.00022

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