SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '869cd6aaa43be68dc793f353a6a063d67dce8564bfb39c57369da05f63956683' 
  AND token = 'Qu+rVuiHhRLr7KPg5ZPjXh17DSRVvJNPY6AmTGVx9OI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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