SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd14663f5c7569718a33b11753961aa5f26d5ca11608d8a86d9f005020e49220f' 
  AND token = 'SE8xbuwympAh0TsW0thhMK1MU3sZYnQr14YVMBlY67Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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