SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '33a7326c1a8f930f7d3971b728b65cc52fe7b8a074e69378d42d8b8f7e335eaf' 
  AND token = 'rzkU5jJcZG/2f6kqefO3WRUlTGcsK/wiRQcLHlYjCDg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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