SELECT 
  1 
FROM 
  cscart_june_setupec_print_temp_designs 
WHERE 
  session_id = '5HFH-3TX7-U3AB-9CGO-VHMO-6RS6-RIUJ-9AO9' 
  AND product_id = 37 
  AND expires_at > 1781761896 
  AND confirmed = 'Y' 
LIMIT 
  1

Query time 0.00042

JSON explain

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