SELECT 
  product_id, 
  amount 
FROM 
  cscart_warehouses_sum_products_amount 
WHERE 
  1 
  AND product_id IN (
    276426, 276427, 276428, 276429, 276430, 
    276431, 276432, 276433, 276434, 276435, 
    276436, 276437, 276438, 276439, 276440, 
    276441, 276442, 276443, 276444, 276445
  )

Query time 0.00025

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}