SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '602f3939aec21fb26e6df44547897a051e5df38fa23b321156f2e7f6645778dd' 
  AND token = 'UBHTjptMYgCyhdX8nHYwHIQJRN2zqBII+zG1GhGcyvk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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