SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd6f7b49da812b01a9eb5094d483d5fe36322bbf9e2e0d8e56c694acc434f9424' 
  AND token = 'mQ4sfYZLkHC+d1gtkKaFtZWCJe9u096TSVh+rjQfew0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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