SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '12d68e1374bd5c88594165f84212deca940b7a9e6cdfa2a96d334e60f824dff9' 
  AND token = 'gZGgs+JP7NIOekZVhd2KVAvRHulzsMhL7+1+plKdXtQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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