SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'bdda6df6a64f1791c6620823c72663010235602e63fbd133cac57d70342fb61e' 
  AND token = 'PTgqQxBhfjF14cRNYlOwsM4a3T3q7WAXoAqIa4DWO7M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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