SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6059b21a819c576e64fb9eefdcf66dba6e15e9a6a428364a2f2da959b1c53dc0' 
  AND token = 'nNMhzHd3jw7j0tOAaVWquN7qp2SIzZUQ/ByNwQp7YTQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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