SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4bfdc038a1b3f3bd1747a050c88440a5f7133d71cf9d7e03642796d241978fd9' 
  AND token = '/pXKwj6pU+ySgLOJNRtNEYM8rRwu6mZXsAuAqv7HO0w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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