SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ef0829bc06b3f58009c7abe3c67f224de6014cbd0faa98aef561ca5cdf83da37' 
  AND token = 'A1WXyMTYfgwtCLmehWk//5jz9ujmRVnWaJJQudXQJC8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}