SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd223fe4d3dfbc4a92414cf237f1ebe016bed5ad567e577669b588b61138633e8' 
  AND token = 'eIe6DtjnKONHWRUXeTwx6HznT+aPE/QWr73NkBOuxR4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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