SELECT 
  1 
FROM 
  cscart_ec_print_temp_designs 
WHERE 
  session_id = 'T7PP-3MWC-PVOF-CIJ8-Z2EE-O7DL-ORHE-H2UN' 
  AND product_id = 223 
  AND expires_at > 1770796628 
  AND confirmed = 'Y' 
LIMIT 
  1

Query time 0.00070

JSON explain

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