SELECT 
  * 
FROM 
  jmj_product_feature_variants 
WHERE 
  variant_id IN (
    3246, 3247, 3014, 3021, 3039, 3047, 3054, 
    3055, 3059, 3063, 3066, 3068, 3074, 
    2103, 2131, 2206, 766
  )

Query time 0.02099

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "40.81"
    },
    "table": {
      "table_name": "jmj_product_feature_variants",
      "access_type": "range",
      "possible_keys": [
        "PRIMARY"
      ],
      "key": "PRIMARY",
      "used_key_parts": [
        "variant_id"
      ],
      "key_length": "3",
      "rows_examined_per_scan": 17,
      "rows_produced_per_join": 17,
      "filtered": "100.00",
      "index_condition": "(`jmj_test`.`jmj_product_feature_variants`.`variant_id` in (3246,3247,3014,3021,3039,3047,3054,3055,3059,3063,3066,3068,3074,2103,2131,2206,766))",
      "cost_info": {
        "read_cost": "37.41",
        "eval_cost": "3.40",
        "prefix_cost": "40.81",
        "data_read_per_join": "26K"
      },
      "used_columns": [
        "variant_id",
        "feature_id",
        "url",
        "color",
        "position",
        "abt__ut2_color_style",
        "abt__ut2_multicolor"
      ]
    }
  }
}