SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd552ff40914123e6cd16df4aaefaee1cf963493c1e01c0dc562e2871639a5ec1' 
  AND token = 'POBDWRzSauRUCVjix+8GgObLOylnUECAV5Kw7MmW+WQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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