SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6ef890299bad38cffad8e03f56e48fb2917ae5da45db2f91f16775f509d6db83' 
  AND token = 'XEz7V94JHLcF6GgdlqYsMqohAineJ/e1HKa3NC7kUBg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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