SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b9568848c657c00ef040d573b191b0289c47816bd20f1adfecc076e106c466d9' 
  AND token = '1QHbRsnZ3Kq+7uZVbVljXM8+UMPt+UO2O6MDkxLU9fQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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