Sandbox

SELECT 
  product_id, 
  amount 
FROM 
  cscart_warehouses_sum_products_amount 
WHERE 
  1 
  AND product_id IN (
    797, 796, 795, 792, 787, 786, 782, 819, 
    781, 765, 764, 763, 762, 760, 758, 752, 
    751, 750, 749, 747
  )

Query time 0.00015

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "Impossible WHERE noticed after reading const tables"
  }
}