SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a56aad270d21820d5042421fff0f0f801a7e234210f65f251e7a4dba8366a21c' 
  AND token = '2myxX0qFAGSaw7pIKQ+fA94uhWpO0e0h2kVvb/0sjaM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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