SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '888e446a066385b817863b3d77701f3b032a86714cc830ddd41c79b0e3569f0a' 
  AND token = 'cKvRIeAxWcFuVBeTPLy/wZt+KQWvtNJYdnP8hPQS2UE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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