SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '395685dbfce9468cb09d3278de85eb997309fbecab28f2fd74eb7cba33e34bc9' 
  AND token = 'FnOSF2OXjX+7g5dtqS13fjtM4DoVfFbkG+tXLcuaD9w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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