SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '72a86117e03766894be54e182c53508edbaa78cebe7d5fc237c69c78f4acf098' 
  AND token = 'exUskjCVroroODzDTEH4epfLYm9YKC8guf7UnfMUwCU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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