SELECT 
  * 
FROM 
  cscart_product_feature_variants 
WHERE 
  variant_id IN (
    577, 591, 1476, 1, 1471, 164, 122, 121, 
    127, 120, 123, 152, 146, 50, 57, 1472, 
    147, 30, 98, 1475, 376, 165
  )

Query time 0.00043

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "15.41"
    },
    "table": {
      "table_name": "cscart_product_feature_variants",
      "access_type": "range",
      "possible_keys": [
        "PRIMARY"
      ],
      "key": "PRIMARY",
      "used_key_parts": [
        "variant_id"
      ],
      "key_length": "3",
      "rows_examined_per_scan": 22,
      "rows_produced_per_join": 22,
      "filtered": "100.00",
      "index_condition": "(`test_uchur_k`.`cscart_product_feature_variants`.`variant_id` in (577,591,1476,1,1471,164,122,121,127,120,123,152,146,50,57,1472,147,30,98,1475,376,165))",
      "cost_info": {
        "read_cost": "13.21",
        "eval_cost": "2.20",
        "prefix_cost": "15.41",
        "data_read_per_join": "34K"
      },
      "used_columns": [
        "variant_id",
        "feature_id",
        "url",
        "color",
        "position",
        "abt__ut2_color_style",
        "abt__ut2_multicolor"
      ]
    }
  }
}