SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd9f2ebd1192725dbbc189832f2c94e3d974b248d3ab396805e36e821bf8ab904' 
  AND token = 'Ycqav2l5JHu9hlFxeYAw5+aFFZfkfwDe+WqroJt+yBA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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