SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4c9812fca71979f7bfd0924ba6910235f327bce930f958e385b8775407cd44d8' 
  AND token = 'H5MHLd5Tvqf+78lZhRjK+aKQJUBBrHLce1H1fa+zQr8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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