SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a46ded5027674e1eea276f42d547ec57693a2f5ff66afdccb140c4a3bbdc849e' 
  AND token = 'ugSzH+qUpjmcluUuOfT/nx16a3St48WzM474LUz95Z8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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