SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '680a831bec595b522330786f0cece3be9701384951ffabf74e7c86b45e713dfd' 
  AND token = 'sfAlnoDmjnHdSGChTGiVT7qV4+aggglpvYX5WJU72uI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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