SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4871c822222fb585e70f353fe855aacdec7afb2701455cfb83c85f15d30408f2' 
  AND token = 'nsZZyK+s9LRVkQDOLYOA1nQur9Fc4diTH+OOutlZzWA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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