SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0349aa0c292877edc8fd88ab7b3baac18f88a6b974374db154dd86d265d8d6ed' 
  AND token = 'tZlNbl51Z0+ulcHKmhmhYFOXpwcS81JpzzPovFb73pc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00055

JSON explain

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