SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2bcbce1cb90c6c6f1c8ed509075421dfb02b4d56a26cdd03f39d7b51c9a00373' 
  AND token = 'TDzhkedFJ/XUoQt+6PmR7TwwnBWz8oifhB+HXFGtZms=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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