SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2b29535db659d663a87317c60550b47720bb2deaeb5e7cd447cc83a08846a621' 
  AND token = 'wE/qiGViMacUzRuxUSA8hmHc9W512vjVIQBelOkkO94=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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