SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9826a9d5966c20d2bd4ee9a080b9fe6a3fabe325241e85f12857924cb0fa2600' 
  AND token = 'ocz4CsLIrTeImKUCqA+3qxqsprlyfWXLo+EKgVrotMY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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