SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4122e16c1d9cb467b7022c79faa229d6eb510fe5f00b01dc578b7ac5e87171b1' 
  AND token = 'ItKPYUdD8KCwxFJxSkNABPp8dvUcSaDO29rmJnAyhjc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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