SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1361a2746f7036618de7a0030118e55183e3b07ead64f1960d03415ad95f43ed' 
  AND token = 'CkwdX/JdDXpMQTdvVL7TUysl5+I1tK0a8QmIpwBd6tI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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