SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5e4788eac2615dc70be4865953e54edc9bdca6083872eeafc671fbd9b4b2ae4a' 
  AND token = 'PFngb0HjacTbO8GWpnhvMVpMr47mKWpam0T9T7TsrmM=' 
  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"
    }
  }
}