SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '141254db4f7a41de8a95bd9f3eec5ce1029b3dee55f641a8516102811a42d7e6' 
  AND token = '9XMjTaJGkthgo/eW13kdwPFJcD8neOuSQosh172rgYg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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