SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2f757866bcfe88c3e69e292c6ca742146f895fc125be9f76712223e621d83882' 
  AND token = 'g71/Su2wKCrmEI4mLJHOQRDmanL/Zo7iYFdNmkTPfyk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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