SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '610b22713c93317e0461957cc34713ad790833d13accb9419049bd271681d75f' 
  AND token = 'oL6TopTZqxfPnxizup/CsxNsEtjsxLv2Y/HJhmlDXpg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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