SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8a1170b059c8058703a7f4406814a360a6f254d1ecf5db440a1faed9101034e6' 
  AND token = 'ZdRfMhYZoIXb+OOlrHbLBvEyePTESX6n+pirVYHdVt4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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