SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '92c9568662520784b1ab0240014eb2d45fb7b4aaff4722676725c53aee2c819f' 
  AND token = 'oH+KFMrAMFP/Ba98rTxzZJWNp20SjfGhK7WO9+sdl6g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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