SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4bbbdbb6750b9b551fc125a84e7df327e78505258c626772cedcf895fca662aa' 
  AND token = 'Ym94BKuUy8m4PDSsCxgv3rpP5bsKYI6gYZnYnqHnDFY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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