SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '86407b5346fb050071d63e1092750b674228d818cd9ac797ade053c9cd2830b3' 
  AND token = 'T+1OfkK1h9VP1Oh+vjGV/pAg+uiaCQuOWik6B1g6Ml8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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