SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '894a466ca5a35103ca5b156440131325191e96fbd8de9df98e395a703ea93d90' 
  AND token = '1rA9EepdI2ZtZBxmVYa13IJp43+lR/Fqzs2NM9Scfw8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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