SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c5fd97f3c9b9f8e7005032041d90b42c41a2389574262954834642ef1a6744ec' 
  AND token = 'WKspDAz+N8utNtq5iWKpj33s7NELByJRnD5AP8fMrXk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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