SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9a43236d2323c52014a6bca3bb22163e4713a51d5b01ddfd3eee44c8adf91c2d' 
  AND token = 'FJjQK12C4iFiO/xuIHhmVEzMZCGgyaf76kzDgpxdkrc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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