SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '67e0ce02d17f557e1b6fbb5004e943587391e2b67643dfce46b6ca8e4bddc1ac' 
  AND token = 'ZeagVwwK+VizyYNlesR5ih8n5ldeasy1QNPjUpJM6eU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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