SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c89e382b974376cccacffbe758026991b35e5de8bd8b9c9d2302cd4b5faf1d56' 
  AND token = 'SubpWGdOK0JdUQk2lRFLd8bGPs97Kq9ORhVgNyJ2lts=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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