SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '77b31bc7f6cf4da3e6431c8d12f34d35e46f0c2a34a335ef969ca954311f18dd' 
  AND token = 'ooM3UxY/SQQMBnr5Rm0DlTTUeoeFb6POKSO4pMSfvP8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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