SELECT 
  1 
FROM 
  cscart_aprilec_print_temp_designs 
WHERE 
  session_id = 'JV4J-1YW7-2FSD-WX8T-57NK-W5QL-TRI1-JYEH' 
  AND product_id = 42 
  AND expires_at > 1777203071 
  AND confirmed = 'Y' 
LIMIT 
  1

Query time 0.00040

JSON explain

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