SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9561197c1726f3b0248d8e3e298306c15dfbede6d4cd1c094322594b405d4f87' 
  AND token = 'wQZ/OTPJrWgv8WKxvF/AjLTrXzLFGNs1mI62r9wk6MM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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