SELECT 
  * 
FROM 
  cscart_vd_vendors_relationships 
WHERE 
  brand_id = 194

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": 12,
          "filtered": 100
        }
      }
    ]
  }
}

Result

id brand_id feature_id variant_id lang_code
13788 194 661 2198 es
13787 194 649 1926 es
13786 194 648 1905 es
13785 194 654 2142 es
13784 194 654 2141 es
13783 194 654 2137 es
13782 194 647 1889 es
13781 194 662 2211 es
13780 194 660 2187 es
13779 194 658 2180 es
13778 194 652 2102 es
13777 194 652 2123 es
13776 194 652 2118 es
13775 194 646 1887 es
13774 194 653 2128 es