SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '487a4cbd06608a5b17126bcbce3793ed1d4e1aed8e03f912d22091079207b3e4' 
  AND token = 'zQVajtgptHG9sChZhodzZ+i8YdsVAzjYooAGBJV08fw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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