SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dcded7d6147d3b5af58da69155c29471def47d60a99720b88eb52b6ea8739566' 
  AND token = 'arZ/GOKaCcfJ4dXPIT+XuKsP/ep0sKDLk51znIPQYh0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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