SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5c0a834b2be7209c7ab03245b277137341beee9e5b39efe69f2adb15d1e5d98f' 
  AND token = 'VIThbEV+nzwnxH/2Hqdl3YyFSWVx0KN6H8g6ZhXJSjk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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