SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '98f761882fb12da88db3bf751f875d6b1b894ffdb87a63948e5098fd4c504d37' 
  AND token = '/M44wSO8Uj7Yz5jXcGTKgfE8JsqiQY9A+8ddVGtE+qI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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