Sandbox

SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '721835ef2f1bc2c067ac38ab1b02e828b1b03837d36837c3fdc3ebd5ab2ba337' 
  AND token = 'E9Adl+5JJ74ECFEGEmHyvuG9C5j4ZTm+JavrhDDYJHU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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