SELECT 
  1 
FROM 
  cscart_june_setupec_print_temp_designs 
WHERE 
  session_id = 'V14P-JP2U-91B8-1XRV-LQAG-A2YE-MN89-B7WX' 
  AND product_id = 102 
  AND expires_at > 1781888331 
  AND confirmed = 'Y' 
LIMIT 
  1

Query time 0.00032

JSON explain

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