SELECT 
  * 
FROM 
  cscart_vd_vendors_relationships 
WHERE 
  brand_id = 94

Query time 0.00045

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": 16,
          "filtered": 100
        }
      }
    ]
  }
}

Result

id brand_id feature_id variant_id lang_code
1638 94 653 2130 es
1639 94 646 1886 es
1640 94 658 2186 es
1641 94 660 2188 es
1642 94 648 1905 es
1643 94 649 1925 es
1644 94 649 1926 es
1645 94 652 2105 es
1646 94 652 2103 es
1647 94 652 2106 es
1648 94 654 2137 es
1649 94 654 2140 es
1650 94 654 2141 es
1651 94 654 2142 es
1652 94 647 1889 es
5795 94 661 2198 es