SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f13f06f6a96d4131e3c766cf942739ca3473a3235f54c0ee4c64d7be5a7f3167' 
  AND token = '9tjv9WqwsWxifEUMFYoIZu9sWd0GrWPsriq4ID2gNgI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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