SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3fa27e00754ca5b7439be48dd594b7cd401e3178b208c98eb2f1fc1b368f0930' 
  AND token = 'nczNZybi2SqfMTfjbVyZUijnGo6NDt0FsY0TTW4tYUg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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