SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8ac9c63428813d8b4108b4d199e9ea123626e539d38b4d754e98ad1bd95017f1' 
  AND token = 'gC6DUxpXnnItPLNVYwUH3xypAIaeqMEh9Jhmb9UuulM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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