SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f8806d2d6f15ead86ee1ceab5a6d33df1edaa4ef6fc31056bb3511cbccb9ffcf' 
  AND token = 'ECH4nrJNujjT+Xz+ajnya5cOdoi6TbjEYOd/V5DC8TU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00048

JSON explain

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