SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '858953e4cc422af0313812229260ee778e86a418dfc2df7f717b7e174e711fe6' 
  AND token = 'tO6k8n/ynfJl+uXP/heLH3OvXTYrCt0ht9rspJ0I7oU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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