SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '23c5f59e4b46f5640473ffb37d68031152abc89bc909700582d1926fe1770a22' 
  AND token = '9LnUjAS4PDzlggRiG9b4/JY2jsI/1zSAkUYrghbYkP0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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