SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '979617282186d9ca30bc046090169074570457c08fb81016cedb7bfb03711b95' 
  AND token = '2SUaW5tcBbPrM7qTB59sWjTJwjwU5ypJDGti70kUGJE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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