SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '47b14a53f94d9d3da5cad33978e83c060b658d6f96b21e71e4677b52a8a744aa' 
  AND token = 'o4eqjiMlwYiUh9Gr39tSVWvWkJgZogJ6+tnKrjs9tLo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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