SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '77799921b6ec18f954df935c12d75b14726a61348befd66fbf2e11ed906b6de2' 
  AND token = 'MMHdo0LEPu3YjnKCqmzzjsF/oHsKtkeJQ7YlHu/ZkdU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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