SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8ed6cef5919361ca0756e9d9e2e7f5b85238f34826b833dd7fa3e9c4f3bb1303' 
  AND token = 'NvR5C8Pq6yVjPVINNy+yzZq7tgmlTizAbaMyD7sKUpw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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