SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cf2943d8e065c906919c4263b823d97674764fac94d743160061baef93518831' 
  AND token = 'YhAgaWazoeNxk3JNncUI7PQDFWtqhjoenHfwx4YmD2U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

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