SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '273251b97de926d8d968319c51c071f872dab03d8c57737f3d00a366fbf98024' 
  AND token = 'XlXgQGHhe3v5dtUnlzCNyEG7ZHJOwLYzmKCBuPbpjtw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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