SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8265ddf0df18ab1b2c1792bc9b1eeeb728dda9d81ccc1f1b1de84723b0867b63' 
  AND token = 'gBb5ke0tCxpIJEYlWT0qXC7mHWuZQ/lOJSEMZLUoXrM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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