Sandbox

SELECT 
  1 
FROM 
  cscart_aprilec_print_temp_designs 
WHERE 
  session_id = 'A1EQ-9DG9-B5UH-KK3L-Y1KF-WZ4S-EE0X-NFPC' 
  AND product_id = 144 
  AND expires_at > 1777914678 
  AND confirmed = 'Y' 
LIMIT 
  1

Query time 0.00021

JSON explain

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