SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '6fe731b978e242bb3d77b3d6b5c838ad5545f52d2881af60f1ff8081b385afd8' 
  AND token = '7j6QFrlly4fkZDk7hqUsCeGu4NoR97CUwA/pnIOwr14=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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