SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3fc7f85f8af4a006c314915c5482485111b72027191fb45a3c9f324f4b7689e2' 
  AND token = 'hUklFgIEeAYOKjhFJh/vxpHyoZTdE0SJ9wTjbUh36AY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}