SELECT 
  variant_id, 
  color 
FROM 
  netting_product_feature_variants 
WHERE 
  feature_id = 572 
  AND variant_id IN (6862, 6863, 6861)

Query time 0.00037

JSON explain

{
  "query_block": {
    "select_id": 1,
    "nested_loop": [
      {
        "table": {
          "table_name": "netting_product_feature_variants",
          "access_type": "ref",
          "possible_keys": ["PRIMARY", "feature_id"],
          "key": "feature_id",
          "key_length": "3",
          "used_key_parts": ["feature_id"],
          "ref": ["const"],
          "rows": 3,
          "filtered": 6.666666508,
          "attached_condition": "netting_product_feature_variants.variant_id in (6862,6863,6861)"
        }
      }
    ]
  }
}