SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'cf51944d8d8714c3b2f8f617f9e5b1b57928b05d376d0569784abfeb6a82ad3d' 
  AND token = 'XLj8eNa92kv0/5gORZfMI869V5z8wnljqWKNEj7BBGw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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