SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7dc83bbae9cd970069e95a51872261f2ee579e7caf05f2138762fe3848165669' 
  AND token = 'xGM3c1I8nkalj+lv0EFAwPA62FyWpWEps/qlvkZ2Eus=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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