SELECT 
  * 
FROM 
  cscart_product_feature_variants 
WHERE 
  variant_id IN (
    1892, 1855, 2470, 1930, 1580, 129, 1856, 
    1870, 0, 1353, 486, 489, 1448, 43, 895, 
    356, 1020, 214, 44, 1451, 136, 121, 710, 
    45, 490, 46
  )

Query time 0.00049

JSON explain

{
  "query_block": {
    "select_id": 1,
    "nested_loop": [
      {
        "table": {
          "table_name": "cscart_product_feature_variants",
          "access_type": "range",
          "possible_keys": ["PRIMARY"],
          "key": "PRIMARY",
          "key_length": "3",
          "used_key_parts": ["variant_id"],
          "rows": 26,
          "filtered": 100,
          "index_condition": "cscart_product_feature_variants.variant_id in (1892,1855,2470,1930,1580,129,1856,1870,0,1353,486,489,1448,43,895,356,1020,214,44,1451,136,121,710,45,490,46)"
        }
      }
    ]
  }
}