SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f46a4c64673f17dc5d040b53c7ed9a45cb44fcd06228ffcc66ce86611a7cb3a9' 
  AND token = '6tiVk3g9ShTOwwhwP3rWzvOgFVezbpyCnvDWnDtBra0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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