SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd8b2fe661544c7bf378f2caa1fb3af57b651e1ea73407ccc281f1ca1b4c5e9b9' 
  AND token = 'guXHlyLHwz+mMVa2akae5XZQBSW4HQWU26bBxiAxOg0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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