SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '40d80dd71a27ef34869cff40f31305c08f7dde5f66e1c75b79a9b290345a079a' 
  AND token = 'g8QKAOHyIi/yayDM3SVFqm9U3auFXgfsoOmlotSNhoc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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