SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b57495c05378cb07c7f8ae5988638a865f5fa2189c88aa58f601b06d386af6d0' 
  AND token = 'y6MJBrhht30HWoao+TVRqUQIG9OpsShbxh8CzIvAntM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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