SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '782f052316f81783b951f6371369e88c713018b7c09afe504c9c379f0423fc31' 
  AND token = 'XNfdylGDTMsU7eKgE/8xkZb0OfDSHe0rI/5Xh+AqJF4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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