SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '40455e8b66ad1c5762e05f1b7bdfbe891e3a8c68f743d947bcd4c46919df53a8' 
  AND token = 'rmqkR+PLbasalrPbnsnS9/MLnpDPjgX/eoCJrMOGsNw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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