SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2855ebbae32dd364a0ddb5fea3641739a575aa3acbe2e734e291526ce03a1502' 
  AND token = '3QkouZ0BvL2WPUocztWx0scDXCH/oErlVVO61UKtDOY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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