SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '16d67a4ade5f9093b3207069e4dff10cb6034208149068e39548054b255bfe8e' 
  AND token = 'DUF6SeyK6AidRITMnMaq2u2u2qEGfRtxjszvL3iYbdI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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