SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e9c74af9722e00867670d510ee0172c5346ae22d7c31882037867a63ff064776' 
  AND token = 'FddsxeOwpIoWH3mlTzeoHU6r8mx83uKRsC3qMsyPQeQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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