SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '47edf12d7ee986eff27ea246e654b49caf54ff3f1c53a7ff917c5475df328fbb' 
  AND token = 'w4fU6z+bSP78uFiBjPsgdh7KcA1tvzTnrcBB5jGwIjk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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