SELECT 
  * 
FROM 
  cscart_abt__ut2_mv_vendor_custom_metadata 
WHERE 
  company_id = 3 
  AND lang_code = 'vn'

Query time 0.00028

JSON explain

{
  "query_block": {
    "select_id": 1,
    "nested_loop": [
      {
        "table": {
          "table_name": "cscart_abt__ut2_mv_vendor_custom_metadata",
          "access_type": "ref",
          "possible_keys": ["PRIMARY"],
          "key": "PRIMARY",
          "key_length": "10",
          "used_key_parts": ["company_id", "lang_code"],
          "ref": ["const", "const"],
          "rows": 12,
          "filtered": 100,
          "attached_condition": "cscart_abt__ut2_mv_vendor_custom_metadata.lang_code = 'vn'"
        }
      }
    ]
  }
}