SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6f9069a440d8bbd85aee056e800c70aa36e8fe447b2d94de972e1e248ae2d1b7' 
  AND token = 'PHjNc7cL9Q7jEhGF5aNjtzgSr8MDoMyskmxlR+4Wykw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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