SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5bde77aa3485996a276dfc8d34027ab6ca8cbca630c147821e8d582c783c4ccf' 
  AND token = 'pVajFaNEZQ7pU3FXaqMKvWVTQcIYdrgB5VszVd1t9hQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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