SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '200613a75033c5c9f02948d0542bba826f720e297c9565fcc3cdc3dd6a995a95' 
  AND token = 'jraWSOGoDZeF/kR4LgKgFag3+pmTJWfCAoTSysEcA5M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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