SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3551b695479809eace8a35ba9f2f075dab0fa1746adf5b0739fca5fe58a8c0bb' 
  AND token = 'WKydJfosQrBsWtJgaHT1rExwSAnCYU0taJBib1aWCW0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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