SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '19e7099b7282e8e9b4a491aa34bec3650e1e5b515e04072045f9e42fd395aa8d' 
  AND token = 'Gzq1inw5Py0Mp8NYH8SvGLr+54cUBVCMM4KUlfj4C78=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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