SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '385fc6dbb34ca5c785b4ca4fca877ed59857dd2516deb8a417618b9f6fbbb290' 
  AND token = 'hlJ9N+xZ5IzK+iUZ3BQr/c2X6fUigRRCcL4LgxwJ5hs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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