SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bf7c2bbb2400eddfadf471ccd8dc859ef2e8ba960628f6c14341b8d00b7a364f' 
  AND token = 'VxJbzmgxruA8/W6xd+nD4XWntofetg35bAO+GsdFr+E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00053

JSON explain

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