SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6cae54074a109685a68e56d9a03ba34a4f9fd81d39f6243dca70d866dc3c79ee' 
  AND token = 'RMWX5MdxYlcasry0WjKQUElpZ6tlrqev/JjbIaDeJno=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}