SELECT 
  * 
FROM 
  cscart_page_descriptions 
WHERE 
  page_id = 37

Query time 0.00074

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost": 0.00183779,
    "nested_loop": [
      {
        "table": {
          "table_name": "cscart_page_descriptions",
          "access_type": "ref",
          "possible_keys": ["PRIMARY"],
          "key": "PRIMARY",
          "key_length": "3",
          "used_key_parts": ["page_id"],
          "ref": ["const"],
          "loops": 1,
          "rows": 1,
          "cost": 0.00183779,
          "filtered": 100
        }
      }
    ]
  }
}