SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '94d38b0121762a1819ade57834ea03c3813fb07ac9ff4e149795863972ddd080' 
  AND token = 'czEJwb6AzRrRaa7jOanMm9tfE7iuJCrJLjWWySfa1V8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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