SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '15cbca486d5ad4788c3170ee4cc6987e32ba94d7a8881e896c56bcf1bf9d3e55' 
  AND token = 'q0rgRVNlWiKrlk+FhZXMbKN92jOXCJC4mJiUzymYofo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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