SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6ba1fdaef991b2f2524251cbd77a7b622ec1dad4ca80491cb70fcdb21604fd7a' 
  AND token = 'UrUFgVTOqPLBCJ8CrqVk0NMplmnBmkabu6zPTz9Hd+s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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