SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4e2f36e4b0398936cb180c17f101853054f916bf13735eb4acbba216e99ba2dd' 
  AND token = 'dgBkQoCj2zB8VDAA7ZLVGFXk0GhWNrQDJovTcB4j4uk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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