SELECT 
  * 
FROM 
  cscart_vd_vendors_relationships 
WHERE 
  brand_id = 107

Query time 0.00032

JSON explain

{
  "query_block": {
    "select_id": 1,
    "nested_loop": [
      {
        "table": {
          "table_name": "cscart_vd_vendors_relationships",
          "access_type": "ref",
          "possible_keys": ["brand_id"],
          "key": "brand_id",
          "key_length": "4",
          "used_key_parts": ["brand_id"],
          "ref": ["const"],
          "rows": 8,
          "filtered": 100
        }
      }
    ]
  }
}

Result

id brand_id feature_id variant_id lang_code
1858 107 653 2128 es
1859 107 660 2188 es
1862 107 649 1925 es
1863 107 652 2116 es
1864 107 652 2103 es
1865 107 654 2136 es
1866 107 647 1890 es
5808 107 661 2198 es