SELECT 
  * 
FROM 
  vi_product_feature_variants 
WHERE 
  variant_id IN (
    91, 108, 109, 110, 89, 84, 55, 66, 73, 76, 
    78, 69, 39, 77, 83, 80, 65, 71, 67, 68, 
    74, 70, 45, 79, 81, 54, 75, 82, 72
  )

Query time 0.00020

JSON explain

{
  "query_block": {
    "select_id": 1,
    "nested_loop": [
      {
        "table": {
          "table_name": "vi_product_feature_variants",
          "access_type": "range",
          "possible_keys": ["PRIMARY"],
          "key": "PRIMARY",
          "key_length": "3",
          "used_key_parts": ["variant_id"],
          "rows": 29,
          "filtered": 100,
          "index_condition": "vi_product_feature_variants.variant_id in (91,108,109,110,89,84,55,66,73,76,78,69,39,77,83,80,65,71,67,68,74,70,45,79,81,54,75,82,72)"
        }
      }
    ]
  }
}