SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '34cb257f34d8c85c07236ec48f25e46d2b04a6f8817646dacf300cf267604752' 
  AND token = 'xKWmfk37WYMk6SZTDdBCjxL+lHdaidQpjlSTG591Ark=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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