SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '18df138188518fbd0dd4d5dd73f5fd65cfcf5ec8d85365e7c54871a04d2f487f' 
  AND token = 't0gBEoY/7lViQTOF7gBMHv7stcpan9pHdA/z0YiKgGQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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