SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8892a99ef92a564c50cbe6cbdfd8775a38087e170994ae6aef132c49e8f87892' 
  AND token = 'T9/lDUjsfBWDzAfuEluwb6z5lVKNFJBMgtOIPXSQUCk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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