SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '516c1ee9f9d8ef5526196a0ee3004c183bbcd211ce9a66db54af1b54bd759db6' 
  AND token = 'MBoxY42XV8WMpUzYf62dx8IpxQHUv+OgVJ3b4aMHmXo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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