SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8b448870de970bcf7e0d33cd039839b45511ca08a30db54f466825a46f8fadd9' 
  AND token = 'JDYefsgaqzS53vtDJGomFfY7/PV7bllkfy2iBAIwjgo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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