SELECT 
  * 
FROM 
  cscart_product_feature_variants 
WHERE 
  variant_id IN (
    3, 502, 252, 366, 125, 172, 296, 148, 414, 
    367, 155, 173, 122, 121, 127, 149, 120, 
    123, 152, 234, 146, 59, 50, 57, 58, 147, 
    176, 42, 32, 33, 31, 44, 43, 26, 298, 299, 
    503, 257, 154, 489, 165, 320
  )

Query time 0.00074

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "29.41"
    },
    "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": 42,
      "rows_produced_per_join": 42,
      "filtered": "100.00",
      "index_condition": "(`test_uchur_k`.`cscart_product_feature_variants`.`variant_id` in (3,502,252,366,125,172,296,148,414,367,155,173,122,121,127,149,120,123,152,234,146,59,50,57,58,147,176,42,32,33,31,44,43,26,298,299,503,257,154,489,165,320))",
      "cost_info": {
        "read_cost": "25.21",
        "eval_cost": "4.20",
        "prefix_cost": "29.41",
        "data_read_per_join": "64K"
      },
      "used_columns": [
        "variant_id",
        "feature_id",
        "url",
        "color",
        "position",
        "abt__ut2_color_style",
        "abt__ut2_multicolor"
      ]
    }
  }
}