SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8e738a210ecf5dd27ed89f16233dd4918bdfeb563fd838c52008598e073754dc' 
  AND token = 'ev7DWxWdSDtHZrHyC+bNTos9Lc+MhCUQMjdNp9MCRXQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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