SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2f3cf8e13be3db11418f32a7c4a3f924551085a6a3f74e0375dcee099fdbeca2' 
  AND token = 'tiLm5DUYVjBxG8kWzyFHFdwqk/DRqsGpCzh9BPo/qss=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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