SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2831159d1c69974fdce02aeb61ae1bf4eaa04dee0f87e64ba5a345b98a008992' 
  AND token = 'ABhJkcYreCYIK1sFChIFdgX1NkYIGIN8MtRpxo7FoKk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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