SELECT 
  1 
FROM 
  cscart_june_setupec_print_temp_designs 
WHERE 
  session_id = '41OP-WDIC-6W6N-8SQ3-Y907-APZ6-J27H-8SDI' 
  AND product_id = 7 
  AND expires_at > 1781764139 
  AND confirmed = 'Y' 
LIMIT 
  1

Query time 0.00021

JSON explain

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