SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dcb83b2e64bba69ded435d22fa3564fe18428822f45bd52ab10bdca6cfbb2ae7' 
  AND token = 'cdfVV0engEK5tZUEF61VGbREsu+931xk5qStfCu2mQo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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