SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f6424773d4ccadec5aa0826bbf98636584165b5ee680b305ee1cd539160e5042' 
  AND token = 'bZJpysLA6CXYKocXOlr1Prh1xPz0EZD0frZ5+rJqGgM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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