SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bb45269867a45635b0ab4dffeeae3bf603c89621d16d4adb6bab42ae61d1a580' 
  AND token = 'FtV3IfougT+dbCTNQ768+lUOVImjBq1oyuDBPGGExOQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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