SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8f93f3dab8f87f30c35d211b4e4ea6afcc03ff0de4df6d6d9b1869f4bbad3dfb' 
  AND token = 'DEUKUKpQvgSNE8pjDljJDJ/mYHVSRI/SF/uakvODG7c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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