SELECT 
  cscart_products.* 
FROM 
  cscart_products 
WHERE 
  cscart_products.product_id IN (
    20090, 20091, 20092, 20093, 20094, 18661, 
    18662, 19131, 18664, 20724, 20725, 
    20728, 20955, 20956, 20957, 20958, 
    20959, 22277, 20971, 21078, 21102, 
    20972, 20973, 20974
  )

Query time 0.00089

JSON explain

{
  "query_block": {
    "select_id": 1,
    "nested_loop": [
      {
        "table": {
          "table_name": "cscart_products",
          "access_type": "range",
          "possible_keys": ["PRIMARY"],
          "key": "PRIMARY",
          "key_length": "3",
          "used_key_parts": ["product_id"],
          "rows": 24,
          "filtered": 100,
          "index_condition": "cscart_products.product_id in (20090,20091,20092,20093,20094,18661,18662,19131,18664,20724,20725,20728,20955,20956,20957,20958,20959,22277,20971,21078,21102,20972,20973,20974)"
        }
      }
    ]
  }
}