SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c35789780e829ed95180d78655e5c56efabfd1fc6a532e155045c3eaef530da0' 
  AND token = '5NHuy9AezuWcHjloxpYJjMWs5nYlKGvaIU+p49TCAOc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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