SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '40896ad255959fd1640432d70f8947f0f7525987407f93449c9c3b6b16b7a5f3' 
  AND token = 'K2tnKmtuzBkXaf50ggUH/cHSDhu68eGwNUjJcg5Q3MA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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