SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '02559944eecfc16643c75059b6666391b6dd9b8d4bd2a9226046a597044b05b5' 
  AND token = 'GaIkNOPm0XyXlve0CAJQ897GIYgaRUQ+4LWV2EdVuE8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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