SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9dd1e82f0cdfc8bee8252884526a3a2f493e7815dbbd35351840f866301f4e66' 
  AND token = 'fvksJyuLH8HnjPSv73upT40TjPGY3XwW2KCrUFui5mA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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