SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '098f8b6fc665236367a117478a41ea9ac4fea87ce7d2cb969ee30c6e941dd12a' 
  AND token = 'bq80AYXiyZLXCiCGhS8JX+pYHv1hJxCFM8wcBx9CCOQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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