SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '63c1fc7c72be842ee4715b729a6167da36613aab4dc43b6cfea9dbefe04080c9' 
  AND token = 'Tk4MdvlHOgnOy/8DmdxdTBhAxJXFtPv4/TiDT3pds1A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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