SELECT 
  cscart_products.* 
FROM 
  cscart_products 
WHERE 
  cscart_products.product_id IN (
    1840, 1841, 1842, 1843, 1844, 1845, 1846, 
    1847, 1848, 1849, 1855, 2915
  )

Query time 0.00034

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost": 0.0216566,
    "nested_loop": [
      {
        "table": {
          "table_name": "cscart_products",
          "access_type": "range",
          "possible_keys": ["PRIMARY"],
          "key": "PRIMARY",
          "key_length": "3",
          "used_key_parts": ["product_id"],
          "loops": 1,
          "rows": 12,
          "cost": 0.0216566,
          "filtered": 100,
          "attached_condition": "cscart_products.product_id in (1840,1841,1842,1843,1844,1845,1846,1847,1848,1849,1855,2915)"
        }
      }
    ]
  }
}