SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4fa970eea0bf763f8f212362fa07cfd67956073cd94e649d105cbadb98af5836' 
  AND token = '3Uw3VFaCVKi5mOetqzGs0X6p45wtfggn8j8SMhXMgWQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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