SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a713d2e05200bc329ee8b06d55090b1046137c8a8e8ba13ac1a7d9a219437ad8' 
  AND token = 'KqAtufIPnwrVRfgNULTVs6kSRXKRYPbiLjljHrWIufU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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