SELECT 
  1 
FROM 
  cscart_ec_print_temp_designs 
WHERE 
  session_id = 'T33G-BDEH-MN0M-ZZ0X-EF3B-RPNV-J9N1-N0Y9' 
  AND product_id = 105 
  AND expires_at > 1770609653 
  AND confirmed = 'Y' 
LIMIT 
  1

Query time 0.00025

JSON explain

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