SELECT 
  1 
FROM 
  cscart_june_setupec_print_temp_designs 
WHERE 
  session_id = 'GL9Q-4PLK-DD91-OE16-T6IT-0796-SVV6-2J69' 
  AND product_id = 40 
  AND expires_at > 1781897003 
  AND confirmed = 'Y' 
LIMIT 
  1

Query time 0.00038

JSON explain

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