SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c62c612816de4c4fa7d8363f48648bfcb9d7af106ab1e018bd1bed4fe2db894c' 
  AND token = 'GuyLjT8JlXAmOUScLk1p9RomfV6+kF6XOUeQWxH/y6U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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