SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '884918a1580eb02fdb2fc5d1a1fc44688280cdab2ecc4b4037bfe975b9272623' 
  AND token = 'zAhyE29lO08bLREdQ9gWgniK29LnInM5pQQS9v4GxoA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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