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SELECT 
  product_id, 
  group_id 
FROM 
  cscart_product_variation_group_products 
WHERE 
  group_id IN (49, 25, 19, 32, 37, 34, 39, 47, 43, 29)

Query time 0.00036

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "table_name": "cscart_product_variation_group_products",
      "access_type": "index",
      "possible_keys": ["idx_group_id"],
      "key": "PRIMARY",
      "key_length": "6",
      "used_key_parts": ["product_id", "group_id"],
      "rows": 126,
      "filtered": 32.5396843,
      "attached_condition": "cscart_product_variation_group_products.group_id in (49,25,19,32,37,34,39,47,43,29)",
      "using_index": true
    }
  }
}

Result

product_id	group_id
111	32
125	34
128	43
129	39
131	47
133	49
135	29
136	19
139	25
177	37
179	19
180	19
191	25
192	25
200	29
201	29
202	29
203	29
204	29
211	32
212	32
213	32
214	32
215	32
216	32
217	32
218	32
224	34
225	34
233	37
234	37
237	39
238	39
256	43
257	43
273	47
274	47
277	49
278	49

product_id	group_id
111	32
125	34
128	43
129	39
131	47
133	49
135	29
136	19
139	25
177	37
179	19
180	19
191	25
192	25
200	29
201	29
202	29
203	29
204	29
211	32
212	32
213	32
214	32
215	32
216	32
217	32
218	32
224	34
225	34
233	37
234	37
237	39
238	39
256	43
257	43
273	47
274	47
277	49
278	49

product_id	group_id
111	32
125	34
128	43
129	39
131	47
133	49
135	29
136	19
139	25
177	37
179	19
180	19
191	25
192	25
200	29
201	29
202	29
203	29
204	29
211	32
212	32
213	32
214	32
215	32
216	32
217	32
218	32
224	34
225	34
233	37
234	37
237	39
238	39
256	43
257	43
273	47
274	47
277	49
278	49

product_id	group_id
111	32
125	34
128	43
129	39
131	47
133	49
135	29
136	19
139	25
177	37
179	19
180	19
191	25
192	25
200	29
201	29
202	29
203	29
204	29
211	32
212	32
213	32
214	32
215	32
216	32
217	32
218	32
224	34
225	34
233	37
234	37
237	39
238	39
256	43
257	43
273	47
274	47
277	49
278	49