SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a99a69db005694093d793beaf7b056ccdedffe541408fa994bde111e6651013d' 
  AND token = 'UOLfRyCv+NvYU7xEQjmGHI2yCa+dlzlPh3tya844gzo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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