SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '15de8613ce9a3feb3f9510fb6fb21eb81a0a6db832d73dbcbf30568a7070f03a' 
  AND token = 'yIopAurusC1TH+tRUDJg79UEnItMmYIlF9lnelt3fuY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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