SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '81d4328b1766200713c7a6b64440e5d5df265a0b0fc812fd17fca71dfef0ac4f' 
  AND token = 'yicUsp6eTe+rzW5YTizkGAA9R5eEvOjPZQBgLNOG24A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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