SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '801f070252ff11f04d2674b716316b981faa233e5cf3a5df4f212c7d748dd28f' 
  AND token = '5PhD83kAXDz7tr8bWacPMb0YluN/JGGVsB325wHFvSg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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