SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '423fda61833d395c18b8088050b06b3fdf46aad799e00b7a3a39a0a932fb9773' 
  AND token = 'Tb03Z9NjE6WG2GS0mlUHRZu0qAW5FYNLhpIQvjGVmwo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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