SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '269d5d993092a185c25aff79d827ced1169378f62e96f843f524fda857f22199' 
  AND token = 'O36UuKGc/rgIEa4Wyof7iSKtPY9ZeeCNoluN7gYrc6Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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