SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5d69d63be13968c811089d2690b649663834a48c75ac22f80fbe2a1156584539' 
  AND token = 'VqbvVtJxeYb9H55ztM0KaMURWgQxY+cfxtlj/MCbuyA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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