SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8f15504cf60cdf185390f9c08fdd98933c17d27ab71649c2332e5e6c58d9476d' 
  AND token = 'J88qTrtdhtzx8xQMBvzjf+PZ6FL29GIRn2mm5GJ2nuM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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