SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dc147602aee8bc90f0c3ad39e18d76c4483c246f3855ee3b5a412228860caefe' 
  AND token = 'xrpji+BqQF61f1JXw0vvLQfGN9fqDuisjzAjvZus9SE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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