SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '031d28c0b9322cadc8562eec6c09a184269176aa31be0c97b7fe78f8a676ce5b' 
  AND token = '33VOIbR4lZbp2Y7hXxPAmykkVcOxNLvmAHhjKWFGO8Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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