SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a3c0c4c1fbc99fa56f7d5c66be06e5fafa63f6390256085ac9bcbcfa7ee05ae0' 
  AND token = 'HFfaDGuJXS+MApoqdlOyC+hNGRKYZyN73lA7HyxE8FE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}