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 (
    12916, 12921, 12956, 12958, 13014, 13028, 
    13040, 13052, 12960, 12974, 12988, 
    13000, 13148, 13153, 12928, 12926, 
    12942, 3135, 12850, 12869, 12876, 12896, 
    12900, 12909, 12752, 12802, 3403, 3404, 
    3405, 3406, 3408, 3409, 6930, 6931, 
    6932, 6933, 6934, 6935, 6936, 3407, 
    2666, 3845, 12796, 12797, 2667, 2668, 
    2669, 2670
  )

Query time 0.00146

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "174.51"
    },
    "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": 50,
          "rows_produced_per_join": 50,
          "filtered": "100.00",
          "index_condition": "(`test2_gaseus`.`p`.`product_id` in (12916,12921,12956,12958,13014,13028,13040,13052,12960,12974,12988,13000,13148,13153,12928,12926,12942,3135,12850,12869,12876,12896,12900,12909,12752,12802,3403,3404,3405,3406,3408,3409,6930,6931,6932,6933,6934,6935,6936,3407,2666,3845,12796,12797,2667,2668,2669,2670))",
          "cost_info": {
            "read_cost": "29.51",
            "eval_cost": "5.00",
            "prefix_cost": "34.51",
            "data_read_per_join": "800"
          },
          "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": [
            "test2_gaseus.p.group_id"
          ],
          "rows_examined_per_scan": 1,
          "rows_produced_per_join": 50,
          "filtered": "100.00",
          "cost_info": {
            "read_cost": "12.50",
            "eval_cost": "5.00",
            "prefix_cost": "52.01",
            "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": [
            "test2_gaseus.p.group_id"
          ],
          "rows_examined_per_scan": 7,
          "rows_produced_per_join": 350,
          "filtered": "100.00",
          "cost_info": {
            "read_cost": "87.50",
            "eval_cost": "35.00",
            "prefix_cost": "174.51",
            "data_read_per_join": "35K"
          },
          "used_columns": [
            "feature_id",
            "purpose",
            "group_id"
          ]
        }
      }
    ]
  }
}