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SELECT 
  product_id, 
  amount 
FROM 
  cscart_warehouses_sum_products_amount 
WHERE 
  1 
  AND product_id IN (
    276635, 276636, 276637, 276638, 276639, 
    276640, 276641, 276642, 276643, 276644, 
    276645, 276646
  )

Query time 0.00029

JSON explain

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