SELECT 
  cscart_products.* 
FROM 
  cscart_products 
WHERE 
  cscart_products.product_id IN (
    48621, 48624, 48629, 48622, 48627, 48631, 
    48623, 48625, 48628, 48630, 48632, 
    48633, 48626
  )

Query time 0.00099

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": 13,
          "filtered": 100,
          "index_condition": "cscart_products.product_id in (48621,48624,48629,48622,48627,48631,48623,48625,48628,48630,48632,48633,48626)"
        }
      }
    ]
  }
}