SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '2b91132709a7c7a50c04ea670b9ac767d281bb718f6c7b5fe90ebd5791403b62' 
  AND token = 'Zj6CSZKY9GnCoXD8ZRrUJ2m1dt1XTDx5pFf/tg9hk2s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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