SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'f29f759f3a3de690164426b75b51daf37ed053e725709fb5d2eef7f2d70a3844' 
  AND token = 'TFPqCmYlcw+en5tZusPRu9g6gda+pVBWWNMfIX1zdJw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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