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 (
    16666, 16941, 16927, 16665, 16930, 16799, 
    16685, 16660, 26620, 16928, 16709, 
    16798, 16929, 17379, 16745, 19139, 
    16694, 19079, 16931, 19134, 16961, 
    16712, 19151, 16655, 16729, 19294, 
    16768, 16845, 26799, 19220, 16743, 
    19069, 18910, 16049, 18489, 19187, 
    19300, 19203, 18997, 18896, 17145, 
    16967, 16663, 19254, 16719, 18825, 
    19105, 16805, 19233, 16746
  )

Query time 0.00132

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "71.16"
    },
    "nested_loop": [
      {
        "table": {
          "table_name": "p",
          "access_type": "range",
          "possible_keys": [
            "PRIMARY",
            "idx_group_id"
          ],
          "key": "PRIMARY",
          "used_key_parts": [
            "product_id"
          ],
          "key_length": "3",
          "rows_examined_per_scan": 51,
          "rows_produced_per_join": 51,
          "filtered": "100.00",
          "index_condition": "(`cscartdb`.`p`.`product_id` in (16666,16941,16927,16665,16930,16799,16685,16660,26620,16928,16709,16798,16929,17379,16745,19139,16694,19079,16931,19134,16961,16712,19151,16655,16729,19294,16768,16845,26799,19220,16743,19069,18910,16049,18489,19187,19300,19203,18997,18896,17145,16967,16663,19254,16719,18825,19105,16805,19233,16746))",
          "cost_info": {
            "read_cost": "30.36",
            "eval_cost": "5.10",
            "prefix_cost": "35.46",
            "data_read_per_join": "816"
          },
          "used_columns": [
            "product_id",
            "parent_product_id",
            "group_id"
          ]
        }
      },
      {
        "table": {
          "table_name": "g",
          "access_type": "eq_ref",
          "possible_keys": [
            "PRIMARY"
          ],
          "key": "PRIMARY",
          "used_key_parts": [
            "id"
          ],
          "key_length": "3",
          "ref": [
            "cscartdb.p.group_id"
          ],
          "rows_examined_per_scan": 1,
          "rows_produced_per_join": 51,
          "filtered": "100.00",
          "cost_info": {
            "read_cost": "12.75",
            "eval_cost": "5.10",
            "prefix_cost": "53.31",
            "data_read_per_join": "19K"
          },
          "used_columns": [
            "id",
            "code"
          ]
        }
      },
      {
        "table": {
          "table_name": "f",
          "access_type": "ref",
          "possible_keys": [
            "idx_group_id"
          ],
          "key": "idx_group_id",
          "used_key_parts": [
            "group_id"
          ],
          "key_length": "3",
          "ref": [
            "cscartdb.p.group_id"
          ],
          "rows_examined_per_scan": 1,
          "rows_produced_per_join": 51,
          "filtered": "100.00",
          "cost_info": {
            "read_cost": "12.75",
            "eval_cost": "5.10",
            "prefix_cost": "71.16",
            "data_read_per_join": "5K"
          },
          "used_columns": [
            "feature_id",
            "purpose",
            "group_id"
          ]
        }
      }
    ]
  }
}