SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '25d0bacd1f06efaa097461478636a8cd6bd1eafe629979178b313304d7878e82' 
  AND token = 'PW59etF3PITnp3nBfA388KZfTAgZvBXrog72J+aVjDg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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