SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '0b775fe70e0da5c66758ae1231cd55c59d6cfb66515d8cd2e9899b52e879a331' 
  AND token = '/mUmWi3n+PqDlFCRT7WhlKxrT+pCCKE4udVHAtdJxB8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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