SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a22e3cf9890ad5023ad7ffd03c322d420fcece84ad9390e1f5854622502d62d6' 
  AND token = 'BfU4nholSIskdhGIE8TjwNe+pZ8UUMlysdwa56W7yhM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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