SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4aa876528c6b5a61cc785769c8803bd0f271f082b9b012266f1d34f74fc90549' 
  AND token = '/fquFPaMzeD9ZdvIH+LgvfRr6rch6VXgGfCeikZ6Q/Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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