SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '7e40681925cc56de327c9fa2ddb9bb00baa8fdbed1751b647f9d9e7394146369' 
  AND token = 'N6wYw/xQMkSFE/2BZ+f6mD+J0suKYioe5EOJutyOrec=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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