SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2c57c619f03bcfdeea0158eb1019cedad01e28b3a20e0b719b0a66d02b76d0ce' 
  AND token = 'LZW9PXAcPIj3U72wiuO9xrMrzhfLsQ4BPxPMpWzqaR4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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