SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ef4b1fe8fb69093e7d9bfa6d8a47c935f97ae07b6bbdaafc3804af8d6163d341' 
  AND token = '3ufrcXrnu5Kjs6asuMDbEbATeG3jfwB6gERKjlJzZBw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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