SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9b82f04b7780fe6467a6913a11d04f2896382eac698660ea452e69bed293472c' 
  AND token = 'f3bwVuHObnZ9U6lTF/wIhpayzeIYlOYOIpDF7DvI7CI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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