SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '5ea2d6f01e27f6a52fa2221e7156d0cb258ed0a599c44e7df20e7520ed4a2d32' 
  AND token = 'UrxVX79XHLcN7qoEUrrUeXFiSnnlvf+FM4O7TZStja8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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