SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '60e6dbd8099f5784388a675d74e78654bf3557310afc531a0fa6fd5b50e0823c' 
  AND token = 'HB2LN8mg129ETrMcVTgblv7fS/isvyvOwdMgYUGZWI0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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